Some Applications of a Programmable Power Switch/Amplifier

Transcription

1 Some Applications of a Programmable Power Switch/Amplifier Application Note April 99 AN0. Authors: L.. Campbell and H.A. Wittlinger Introduction The CA09 unique monolithic programmable power switch/amplifier IC consists of a highgain preamplifier driving a poweroutput amplifier stage. It can deliver average power of watts of peak power of 0W to an external load, and can be operated from either a single or dual power supply. This Note briefly describes the characteristics of the CA09, and illustrates its use in the following circuit applications: Class A Instrumentations and Power Amplifiers Class A DriverAmplifier for Complementary Power Transistors Wide Frequency ange Power Multivibrators Current or Voltage Controlled Oscillators Comparators (Threshold Detectors) Voltage egulators Analog Timers (Long Time Delays) Alarm Systems MotorSpeed Controllers Thyristor Firing Circuits Battery Charger egulator Circuit Ground Fault Interrupter Circuits Circuit Description The CA09 series of devices offers a unique combination of circuit flexibility and powerhandling capability. Although these monolithic ICs dissipate only a few microwatts when quiescent, they have a high currentoutput capability (00mA average, 00mA peak) in the active state, and the premiumgrade devices can operate at supply voltages up to V. Figure shows a schematic diagram of the CA09. The portion of the circuit preceding transistors Q and Q is the preamplifier section and is generically similar to that of the CA00 Operational Transconductance Amplifier (OTA) [, ]. The CA09 circuits can be gainprogrammed by either digital and/or analog signals applied to a separate AmplifierBiasCurrent (I ABC ) terminal (No. in Figure ) to control circuit sensitivity. esponse of the amplifier is essentially liner as a function of the current at terminal. This additional signal input port provides added flexibility in may applications. Thus, the output of the amplifier is a function of input signals applied differentially at terminals and and/or in a singlyended configuration at terminal. The output portion of the monolithic circuit in the CA09 consists of a Darling connected transistor pair with access provided to both the collector and emitter terminals to provide capability to sink and/or source current. The CA09 series of circuits consists of six types that differ only in voltagehandling capability and package options, as shown below; other electrical characteristics are identical. EXTENAL FEQUENCY COMPENSATION O INHIBIT V MODE TEM INV S NONINV Source Q D Q D Q Q D D Q Sink DIFF. VOLTAGE DIFF. VOLTAGE AMPLIFIE BIAS I ABC Q Q Q D Q Q9 Q0 kω D V Q SINK Q SOUCE (DIVE) FIGUE. CA09 CICUIT SCHEMATIC DIAGAM 00HAIS or 090 Copyright Harris Corporation 99

2 Application Note 0 PACKAGE OPTIONS CA09S, CA09T CA09AS, CA09AT CA09BS, CA09BT MAXIMUM VOLTAGE ATING V V V The suffix S indicates circuits packaged in TO enclosures with leads formed to an lead dual in line configuration (0. inch pin spacing). The suffix T indicates circuits packaged in lead TO enclosures with straight leads. The generic CA09 type designation is used throughout the Note. Class A Instrumentation Amplifiers One of the more difficult instrumentation problems frequently encountered is the conversion of a differential input signal to a singleended output signal. Although this conversion can be accomplished in a straightforward design through the use of classical op amps, the stringent matching requirements of resistor ratios in feedback networks make the conversion particularly difficult from a practical standpoint. Because the gain of the preamplifier section in the CA09 can be defined as the product of the transconductance and the load resistance (g m L ), feedback is not needed to obtain predictable openloop gain performance. Figure shows the CA09 in this basic type of circuit. DIFFEENTIAL THEMOCOUPLE I ABC 0kΩ 00Ω 0µA 0kΩ W O E DIFF CA09A kω I O I O 0kΩ L E 0Ω kω NOTES: 0V. Preamp gain (A V ) = g m L = () (0 ) () (0 ) = 0 (Output at terminal ).. For linear operation: Differential Input ±mv (With approx. % deviation from linearity).. Output voltage (E O ) = A V (±e DIFF ) = (0) (±mv) = ±.V.V ( g. m L )( e DIFF ) I O =.ma 0Ω I O E FIGUE. OPEN LOOP INSTUMENTATION AMPLIFIE WITH DIFFEENTIAL AND SINGLE ENDED amplifierbiascurrent. In this circuit an I ABC of 0µA results in a g m of ms. The operating point of the output stage is controlled by the potentiometer. With no differential input signal (e DIFF = 0), this potentiometer is adjusted to obtain a quiescent output current I O of ma. This output current is established by the 0Ω emitter resistor, E, as follows: ( g m L )( e DIFF ) I O E Under the conditions described, an input swing e DIFF of ±mv produces a variation in the output current I O of ±.ma. The nominal quiescent output voltage is ma times 0Ω or.v. This output level drifts approximately mv, or 0.09%, for each o C change in temperature. Output drift is caused by temperature induced variations in the base emitter voltage of the two output transistors, Q and Q. (NOTE ) kω 0kΩ/AM TANSDUCE BIDGE 9.kΩ 00kΩ ±% 0µA 0kΩ CA09 Ω 000pF 0mA.V 0Ω 00Ω CAL M NOTE:. Set to optimize CM. FIGUE. SINGLE SUPPLY DIFFEENTIAL BIDGE AMPLIFIE kω 00Ω ±% THEMO COUPLE 0kΩ kω 00kΩ ZEO ADJ 0K 00Ω ±% 0kΩ CA09 Ω 000pF 00kΩ ±% V M 90Ω ±% 00Ω V OUT V FULL SCALE 0mA mv FOM THEMO COUPLE FULL SCALE CUENT IN9 The gain of the preamplifier section (to terminal No. ) is g m L = ( x 0 ) ( x 0) = 0. The transconductande g m is a function of the current into terminal No., I ABC, the FIGUE. SINGLE SUPPLY AMPLIFIE FO THEMO COUPLE SIGNALS

3 Application Note 0 Figure shows the CA09 used in conjunction with a resistivebridge input network; and Figure shows a singlesupply amplifier for thermocouple signals. The C networks connected between terminals and in Figure and Figure provide compensation to assure stable operation. The components of the C network are chosen so that MHz πc Class A Power Amplifiers The CA09 is attractive for poweramplifier service because the output transistor can control current up to 00mA (00mA peak), the premium devices. CA09B can operate at supply voltages up to V, and the TO package can dissipate power up to.w when equipped with a suitable heat sink that limits the case temperature to o C. Figure shows a Class A amplifier circuit using the CA09A that is capable of delivering 0mW to a 0Ω resistive load. This circuit has a voltage gain of 0dB and a db band width of about 0kHz. Operation is stable without the use of a phasecompensation network. Potentiometer is used to establish the quiescent operating point for class A operation. E IN V 0kΩ 00Ω 0kΩ V 00Ω kω CA09A The circuit of Figure illustrates the use of the CA09 in a class a poweramplifier circuit driving a transformercoupled load. With dual power supplies of.v and.v, a base resistor B of 0kΩ, and an emitter resistor E of 0Ω, CA09 dissipation is typically mw. With supplies of 0V and 0V, B of 0kΩ, and E of Ω, the dissipation is.w. Total harmonic distortion is 0.% at a power output level of 0mW with a reflected load resistance P of 0Ω, and is.% for an output of 00mW with an P of Ω. The setting of potentiometer establishes the quiescent operating point for class A operation. The kω resistor connected between terminals and provides DC feedback to stabilize the collector current of the output transistor. The AC gain is established bye the ratio of the MΩ resistor 00kΩ V V L 0Ω V OUT FIGUE. CLASS A AMPLIFIE 0mW CAPABILITY INTO A ESISTIVE LOAD connected between terminals and the kω resistor connected to terminal. Phase compensation is provided by the 0pF capacitor connected to terminal. V 0kΩ kω Ω 0kΩ kω V B 0pF CA09A Class A Driver Amplifier for Complementary Power Transistors MΩ 0.0µF The CA09 configuration and characteristics are ideal for driving complementary poweroutput transistors []; a typical circuit is shown in Figure. This circuit can provide W of audio power output into an Ω load with intermodulation distortion (IMD) of 0.% when 0Hz and khz signals are mixed in a : ratio. Intermodulation distortion is shown as a function of power output in Figure. The large amount of loop gain and the flexibility of feedback arrangements with the CA09 make it possible to incorporate the tone controls into a feedback network that is closed around the entire amplifier system. The tone controls in the circuit of Figure are part of the feedback network connected from the amplifier output (junction of the 0Ω and Ω resistors driven by the emitters of Q and Q) to terminal of the CA09. Figure 9 shows voltage gain as a function of frequency with tone controls adjusted for flat response and for responses at the extremes of tonecontrol rotation. The use of tone controls incorporated in the feedback network results in excellent signal to noise ratio. Hum and noise are typically 00µV (db down) at the output. P E V V L GEN. ADIO TYPE 0A POWE METE O EQUIVALENT 000µF TYPICAL DATA DEVICE DISSIPATION MW.W B 0kΩ 0kΩ V.V 0V V.V 0V E 0Ω Ω P O 0mW 00mW THD 0.%.% P 0Ω Ω FIGUE. CLASS A AMPLIFIE WITH TANSFOME COUPLED LOAD

4 Application Note 0 In addition to the savings resulting from reduced parts count circuit size, the use of the CA09 leads to further savings in the power supply system. Typical values of power supply rejection and common mode rejection are 90dB and 00dB, respectively. An amplifier with 0dB gain and 90dB power supply rejection would require a mv powersupply ripple to produce mv of hum at the output. Therefore, no filtering is required other than that provided by the energy storage capacitors at the output of the rectifier system shown in Figure. For application in which the operating temperature range is limited (e.g., consumer service the thermal compensation network (shaded area) can be replaced by a more economical configuration consisting of a resistor diode combination (.Ω and N9) as shown in Figure. Power Multivibrators (Astable and Monostable) The CA09 is suitable for use in power multivibrators because its high current output transistor can drive low impedance circuits while the input circuitry and the frequency determining elements are operating at micropower levels. A typical example of an astable multivibrator using the CA90 with a dual power supply is shown in Figure 0. The output frequency f OUT is determined as follows: f OUT = C IN [( ) ] If is equal to.0, then f OUT is simply the reciprocal of C. TEBLE BOOST (CW) kω CUT (CCW) 0.0µF 0Ω D D N9 V 0.µF 00Ω Ω 0.00µF C 0.00µF 0.µF VOLUME 00Ω µf 0 kω CA09B 0. µf.pf Ω LEAD TO 0Ω W 0Ω W 0Ω Ω µf Q N9 Q Q THEMAL COMPENSATION NETWOK N9 0.Ω 0.Ω N0 00µF 00 µf 0Ω Ω V D D D D µh Ω.MΩ L Ω 0V 0Hz STANCO NO. P09 O EQUIVALENT (0VAC TO.VCT AT A) OPTIONAL THEMAL COMPENSATION NETWOK µf kω BOOST 00kΩ CUT (CW) (CCW) BASS 0.0µF 0kΩ TYPICAL PEFOMANCE DATA FO W AUDIO AMPLIFIE CICUIT Power Output (Ω load, Tone Control set at Flat ) Music (at % THD, regulated supply) W Continuous (at 0.% IMD, 0Hz and khz mixed in a : ratio, unregulated supply) See Figure in AN W Total Harmonic Distortion At W, unregulated supply % At W, unregulated supply % NOTES:. For standard input: Short C ; = 0kΩ,C = 0.0µF; remove. C 0.µF JUMPE Voltage Gain dB Hum and Noise (below continuous power output) db Input esistance kω Tone Control ange see Figure 9 in AN0. For ceramic cartridge input: C = 0.00µF, =.MΩ, remove jumper from C ; leave. FIGUE. W AUDIO AMPLIFIE CICUIT FEATUING TUE COMPLEMENTAY SYMMETY STAGE WITH CA09 IN DIVE STAGE.Ω N9

5 Application Note 0 INTEMODULATION DISTOTION (%) UNEGULATED SUPPLY LOAD Ω 0Hz AND khz 0Hz AND khz 0Hz AND khz 0 0 POWE (W) FIGUE. INTEMODULATION DISTOTION vs POWE VOLTAGE GAIN (db) BASS CUT 00 BASS BOOST TEBLE BOOST TEBLE CUT 000 0K FEQUENCY (Hz) FLAT FIGUE 9. VOLTAGE GAIN vs FEQUENCY 00K V circuit. The frequency of oscillation f OSC is determined by the resistor rations, as follows: I f OSC = ( Cln) [( ) ] where: A B = A B MΩ MΩ A B MΩ C 0.µF.MΩ.MΩ NOTES:. Flash/s. I f OSC = ( Cln) [( ) ] where: A B = A B CA09 V NO.. % Duty Cycle. Frequency Independent of V from V V DC FIGUE. ASTABLE MULTIVIBATO USING SINGLE SUPPLY kω 00kΩ kω 00kΩ 0V 0Ω kω 000pF 00kΩ C CA09A Figure is a single supply astable multivibrator circuit which illustrates the use of the CA09 for flashing an incandescent lamp. With the component values shown, this circuit produces one flash per second with a % on time while delivering output current in excess of 00mA. During the % off time it idles with micropower consumption. The flashing rate can be maintained with in ±% of the nominal value over a battery voltage range from V to V and a temperature excursion from 0 o C to 0 o C. The CA09 series of circuits can supply peakpower output in excess of 0W when used in this type of V f OUT khz FIGUE 0. ASTABLE MULTIVIBATO USING DUAL SUPPLY 0kΩ P 00kΩ 00kΩ C 0pF CA09A Provisions can easily be made in the circuit of Figure to vary the multivibrator pulse length while maintaining an essentially constant pulse repetition rate. The circuit shown in Figure incorporates a potentiometer P for varying the width of pulses generated by the astable multivibrator driving light emitting diode (LED). LED FIGUE. ASTABLE POWE MULTIVIBATO WITH POVISIONS FO VAYING DUTY CYCLE 9

6 Application Note 0 Figure shows a circuit incorporating independent controls (r ON and r OFF ) to establish the on and off periods of the current supplied to the LED. The network between points A and B is analogous in function to that of the 00kΩ resistor in Figure. kω kω A IN9 r OFF B r ON 00kΩ C 0pF The CA09 is also suitable for use in monostable multivibrators as shown in Figure. In essence, this circuit is a pulse counter in which the duration of the output pulses is independent of trigger pulse duration. The meter reading is a function of the pulse repetition rate which can be monitored with the speaker. Current or Voltage Controlled Oscillators Because the transconductance of the CA90 varies linearly as a function of the amplifier bias current (I ABC ) supplied to terminal, the design of a current or voltage controlled oscillator is straightforward, a shown in Figure. Figure and Figure show oscillator frequency as a function of I ABC for a current controlled oscillator for two different values of 00kΩ CA09A 0V 0Ω LED FIGUE. ASTABLE POWE MULTIVIBATO WITH POVISIONS FO INDEPENDENT CONTOL OF LED ONOFF PEIODS 00pF V 0V MΩ N9 kω 0.µF TIGGE 0kΩ N9 MΩ 00µF V 0.00µF 00kΩ CA09A V 0Ω M 00Ω 00µF V 0mA V 0V KΩ 00Ω 00Ω SPEAKE N9 ms Full Scale Deflection = P/s FIGUE. POWE MONOSTABLE MULTIVIBATO capacitor C in Figure. The addition of an appropriate resistor () in series with terminal in Figure converts the circuit into a voltage controlled oscillator. Linearity with respect to either current or voltage control is within % over the middle half of the characteristics. However, variation in the symmetry of the output pulses was a function of frequency is an inherent characteristic of the circuit in Figure, and leads to distortion when this circuit is used to drive the phase detector in phaselockedloop applications. This type distortion can be eliminated by interposing an appropriate flipflop between the output of the oscillator and the phase locked discriminator circuits. kω kω 0kΩ N9 00Ω C CUENT O VOLTAGE CA09A kω V FIGUE. CUENT O VOLTAGE CONTOLLED OSCILLATO FEQUENCY (Hz) SUPPLY VOLTAGE V = V 00 C = 000pF TEMINAL NO. TO GND IN FIGUE AMBIENT TEMPEATUE T A = o C AMPLIFIE BIAS CUENT (µa) 00 FIGUE. FEQUENCY vs I ABC FO C = 000pF FO CICUIT IN FIGUE FEQUENCY (khz) SUPPLY VOLTAGE V = V C = 000pF TEMINAL NO. TO GND IN FIGUE AMBIENT TEMPEATUE T A = o C AMPLIFIE BIAS CUENT (µa) 00 FIGUE. FEQUENCY vs I ABC FO C = 00pF FO CICUIT IN FIGUE 0

7 Application Note 0 Comparators (Threshold Detectors) Comparator circuits are easily implemented with the CA09, as shown by the circuits in Figure. The circuit of Figure A is arranged for dual supply operation; the input voltage exceeds the positive threshold, the output voltage swings essentially to the negative supply voltage rail (it is assumed that there is negligible resistive loading on the output terminal). An input voltage that exceeds the negative threshold value results in a positive voltage output essentially equal to the positive supply voltage. The circuit in Figure B, connected for single supply operation, functions similarly. ± THESHOLD = ± SUPPLY kω A 00kΩ 00kΩ 00kΩ = kω B 0kΩ 00kΩ CA09A V 00kΩ FIGUE A. DUAL SUPPLY 00kΩ CA09 Figure 9 shows a dual limit threshold detector circuit in which the high level limit is established by potentiometer and the low level limit is set by potentiometer to actuate the CA00 low limit detector [, ]. A positive output signal exceeds either the high limit or the low limit values established by the appropriate potentiometer settings. This output voltage is approximately V with the circuit shown. The high current handling capability of the CA09 makes it useful in Schmitt power trigger circuits such as that shown in Figure 0. In this circuit, a relay coil is switched whenever the input signal traverses a prescribed upper or lower trip point, as defined by the following expressions: V V V V B A A B B B B B A FIGUE B. SINGLE SUPPLY FIGUE. COMPAATOS (THESHOLD DETECTOS) DUAL AND SINGLE SUPPLY TYPES Upper Trip Point = 0 Lower Trip Point ( 0 0.0) The circuit is applicable, for example, to automatic ranging. With the values shown in Figure 0, the relay coil is energized when the input exceeds approximately.9v and remains energized until the input signal drops below approximately.v. V.kΩ HIGH DEAD ZONE LOW kω 0kΩ.9kΩ kω 0kΩ kω kω V Power Supply egulators 0kΩ CA09 The CA09 is an ideal companion device to the CA0 series regulator circuits [] in dual voltage tracking regulators that handle currents up to 00mA. In the circuit of Figure, the magnitude of the regulated positive voltage provided by the CA0A is adjusted voltage supplies the power for the CA09A negative regulator and also supplies a reference voltage to its terminal to provide tracking. This circuit provides a maximum line regulation equal to 0.0% per volt of input voltage change and a maximum load regulation of 0.0% of the output voltage. CA00 0kΩ 00Ω N9 FIGUE 9. DUAL LIMIT THESHOLD DETECTO 00kΩ.MΩ 00kΩ CA09A 00Ω 0.0µF V 0Ω COIL 0Ω Ω kω.9kω V kω 0V FIGUE 0. PECISION SCHMITT POWE TIGGE CICUIT

8 Application Note 0 Figure shows a regulated high voltage supply similar to the type used to supply power for GeigerMueller tubes. The CA09, used as an oscillator, drives a stepup transformer which develops suitable high voltages for rectification in the IN00 diode network. A sample of the regulated output voltage is fed to the CA00A operational transconductance amplifier through the 9MΩ and 90kΩ divider to control the pulse repetition rate of the CA09. Adjustment of potentiometer determines the magnitude of the regulated output voltage. egulation of the desired output voltage is maintained within % despite load current variations of µa to µa. The DC to DC conversion efficiency is about %. Timers The programmability feature inherent in the CA09 (and operational transconductance amplifiers in general) simplifies the design of presettable timers such as the one shown in Figure. Long timing intervals (e.g., up to hrs) are achieved by discharging a timing capacitor C into the signal input terminal (e.g., No. ) of the CA09. This discharge current is controlled precisely by the magnitude of the amplifier bias current I ABC programmed into terminal through a resistor selected by switch S. Operation of the circuit is initiated by charging capacitor C through the momentary closing of switch S. Capacitor C starts discharging and continues discharging until voltage E is less than voltage E. The differential input transistors in the CA09 then change state, and terminal draws sufficient current to reverse the polarity of the output voltage (terminal ). Thus, the CA09 not only has provision for readily presetting the time delay, but also provides significant output current to drive control devices such as thyristors. esistor limits the initial charging current for C. esistor limits the initial charging current for C. esistor establishes a minimum voltage of at least V at terminal to insure operation within the common mode input range of the device. The diode limits the maximum differential input voltage to V. Gross changes in time range selection are made with switch S, and vernier trimming adjustments are made with potentiometer. V (NOTE ) V (NOTE ) EF.V CA0A VOLTAGE EG 0.00µF.kΩ 00Ω 0.0µF CA09A kω 0kΩ.kΩ 00kΩ V 0kΩ EG ±% 0kΩ ±%.Ω NOTES:. V input range = 9V to 0V for V output. V input range = to 0V for V output. EGULATION: MAX I OUT = ±00mA V EG COMMON ETUN 0.0µF MAX LINE = V OUT 00 = 0.0%/V V OUT ( INITIAL) V IN V OUT MAX LINE = V OUT ( INITIAL) 00 = 0.0% V OUT (I L FOM ma to 0mA) FIGUE. DUAL VOLTAGE TACKING EGULATO L 9MΩ V (NINE MΩ ESISTOS IN SEIES) IN00 900V 90kΩ MΩ.MΩ MΩ.MΩ.MΩ CA00A.µA 0.µF 0pF 0 kω 0 kω 0 kω µf 0kΩ CA09 0kΩ N9 µa N9 0.0µF IN00 MINIATUE MICOPHONE TANSFOME 00Ω CT TO 0kΩ IN00 0.0µF 0.0µF FIGUE. EGULATED HIGH VOLTAGE SUPPLY

9 Application Note 0 0V AC 0V DC COMMON STAT SWITCH S E 00Ω C E µf CA09A TIME ANGE SECTO S In some timer applications, such as that shown in Figure, a meter readout of the elapsed time is desirable. This circuit uses the CA09 and CA0 transistor array [] to control the meter and a load switching triac. The timing cycle starts with the momentary closing of the start switch to charge capacitor C to an initial voltage determined by the 0kΩ vernier timing adjustment. During the timing cycle the output of the CA09, LOAD G 09 TUNS OFF AFTE EXPIATION OF TIME DELAY TIME ESISTO VALUE Min = 0.MΩ =.kω 0Min =.MΩ = 0kΩ Hrs = MΩ =.kω Hrs = MΩ =.kω FIGUE. PESETTABLE ANALOG TIME MT MT which is also the collector voltage of Q, is high. The base drive for Q is supplied from the positive supply through a 9kΩ resistor. The emitter of Q, through the Ω resistor, supplies gatetrigger current to the triac. Diode connected transistors Q and Q are connected so that transistor Q acts as a constant current source to drive the triac. As capacitor C discharges, the CA09 output voltage at terminal decreases until it becomes less than the V CESAT of Q. At this point the flow of drive current to the triac ceases and the timing cycle is ended. The 0kΩ resistor between terminals and of the CA09 is a feedback resistor. Diode connected transistor Q and Q and their associated networks serve to compensate for nonlinearities in the discharge circuit network by bleeding corrective current into the 0kΩ feedback resistor. Thus, current flow in the meter is essentially linear with respect to the timing period. The time periods as a function of and indicated on the Timeange Selection Switch in Figure. Alarm Circuit Figure shows an alarm circuit utilizing two sensor lines. In the noalarm state, the potential at terminal (I ABC ) is driven with sufficient current though resistor to keep the output voltage high. If either sensor line is opened, shorted to ground, or shorted to the other sensor line, the output goes low and activates some type of alarm system. The backtoback diodes connected between terminals and protect the CA09 input terminals against excessive differential voltages. 0V.kΩ 0kΩ STAT SWITCH VENIE TIME ADJUST C 0.µF 0.0µF CA09 0kΩ MΩ.MΩ MIN H 00kΩ.MIN 00MΩ 0s TIME ANGE SELECTION SWITCH 9kΩ 0V 0Hz 9 L 0V Q Q Q Q 0 MT.kΩ kω kω 0kΩ METE EADOUT (000µA) kω M Ω Q kω CA0 G MT FIGUE. PESETTABLE TIME WITH LINEA EADOUT

10 Application Note 0 00kΩ 00kΩ SENSO LINES 0kΩ 0kΩ N9 D CA09 MotorSpeed Controller System D 0kΩ Figure illustrates the use of the CA09 in a motorspeed controller system. Circuity associated with rectifiers D and D comprises a full wave rectifier which develops a train of halfsinusoid voltage pulse to power the DC motor. The motor speed depends on the peak value of the halfsinusoids and the period of time (during each half cycle) the SC is conductive. The SC conduction, in turn, is controlled by the time duration of the positive signal supplied to the SC by the phase comparator. The magnitude of the positive DC voltage supplied to terminal of the phase comparator depends on motorspeed error as detected by a circuit such as that shown in Figure. This DC voltage is compared to that of a 00Ω I ABC FIGUE. ALAM SYSTEM V FO TIGGEING ALAM fixed amplitude ramp wave generated synchronously with the AC line voltage frequency. The comparator output at terminal is high (to trigger the SC into conduction) during the period when the ramp potential is less than that of the error voltage on terminal. The motor current conduction period is increased as the error voltage at terminal is increased in the positive direction. Motorspeed accuracy of ±% is easily obtained with this system. MotorSpeed Error Detector Figure A shows a motorspeed error detector suitable for use with the circuit of Figure. A CA00 operational transconductance amplifier is used as a voltage comparator. The reference for the comparator is established by setting the potentiometer so that the voltage at terminal is more positive than that at terminal when the motor speed is too low. An error voltage E is derived from a tachometer driven by the motor. When the motor speed is too low, the voltage at terminal of the voltage comparator is less positive than that at terminal, and the output voltage at terminal goes high. When the motor speed is too high, the opposite input conditions exist, and the output voltage at terminal goes low. Figure B also shows these conditions graphically, with a linear transition region between the high and low output levels. This linear transition region is known as proportional bandwidth. The slope of this region is determined by the proportional bandwidth control to establish the error correction response time. MOTO SPEED EO SIGNAL SEE FIGUE MOTO SPEED EO DETECTO SEE FIGUE SYNCHONOUS AMP GENEATO N9 0kΩ 0kΩ N9 Ø COMPAATO 0kΩ CA09A V V.kΩ FO TIGGEING ALAM SC DC MOTO 0 LINE D D FIGUE A. TO TEMINAL TO TEMINAL (NOTE ) NOTE:. This level will vary depending on motor speed. (See Text). MOTO CUENT TIME FIGUE B. FIGUE. MOTO SPEED CONTOLLE SYSTEM

11 Application Note 0 E 0kΩ 00kΩ N9 N9 N9 POPOTIONAL BANDWIDTH CONTOL N9 CA00A V 0kΩ MΩ V E OUT TO PHASE COMPAATO positive supply limits the triac gate current and develops the voltage for the hysteresis feedback. The excellent power supply rejection and common mode rejection ratios of the CA09 permit accurate repeatability of control despite appreciable power supply ripple. The circuit of Figure 9 is equally suitable for use with Negative Temperature Coefficient (NTC) sensors provided the positions of the sensor and the associated resistor are interchanged in the circuit. The diodes connected back to back across the input terminals of the CA09 protect the device against excessive differential input signals. ECTIFIED AND FILTEED SIGNAL DEIVED FOM TACHOMETE DIVEN BY MOTO BEING CONTOLLED FIGUE A. VOLTAGE COMPAATO E OUT HIGH MOTO SPEED SLOW Synchronous amp Generator Figure shows a schematic diagram and signal waveforms for a synchronous ramp generator suitable for use with the motor controller circuit of Figure. Terminal is biased at approximately.v (above the negative supply voltage). The input signal E IN at terminal is a sample of the halfsinusoids (at line frequency) used to power the motor in Figure. A synchronous ramp signal is produced by using the CA09 to charge and discharge capacitor C in response to the synchronous toggling of E IN. The charging current for C is supplied by terminal. When terminal swings more positive than terminal, transistors Q and Q in the CA09 (Figure ) lose their base drive and become nonconductive. Under these conditions, C discharges linearly through the external diode D and Q0, D path in the CA09 to produce the ramp wave. The E OUT signal is supplied to the phase comparator in Figure. Thyristor Firing Circuits POPOTIONAL BANDWIDTH MOTO SPEED FAST E OUT LOW FIGUE B. FIGUE. MOTO SPEED EO DETECTO Temperature Controller In the temperature control system shown in Figure 9, the differential input of the CA09 is connected across a bridge circuit comprised of a Positive Temperature Coefficient (PTC) temperature sensor, two kω resistors, and an arm containing the temperature set control. When the temperature is low, the resistance of the PTC type sensor is also low; therefore, terminal is more positive than terminal and an output current from terminal of the CA09 drives the triac into conduction. When the temperature is high, the input conditions are reversed and the triac is cut off. Feedback from terminal provides hysteresis to the control point to prevent rapid cycling of the system. The.kΩ resistor between terminal and the 0kΩ.kΩ E IN D 0kΩ N9 CA00A N9 D D kω N9 FIGUE A. Thyristor Control from AC Bridge Sensor V E OUT TO PHASE COMPAATO C 0.0 µf V BIAS LEVEL E IN AT TEMINAL NO. 0 C DISCHAGING (AMP) C CHAGING E OUT 0 FIGUE B. FIGUE. SYNCHONOUS AMP GENEATO WITH AND WAVEFOMS Figure 0 shows a line operated thyristor firing circuit controlled by a CA09 that operates from an AC Bridge sensor. This circuit is particularly suited to certain classes of sensors that cannot be operated from DC. The CA09 is inoperative when the high side of the AC line is negative because there is no I ABC supply to terminal. When the sensor bridge is unbalanced so that terminal is more positive than terminal, the output stage of the CA09 is cut off when the AC line swings positive, and the output level at terminal of the CA09 goes high. Current from the line flows through the IN9 diode to charge the 00µF reservoir capacitor, and also provides current to drive the triac into conduction. During the succeeding negative swing of the AC line, there is sufficient remanent energy in the reservoir capacitor to maintain conduction in the triac. When the bridge is unbalanced in the opposite direction so that terminal is more positive than terminal, the output of the CA09 at terminal is driven sufficiently low to sink the current supplied through the N00 diode so that the triac gate cannot be triggered. esistor supplies the hysteresis feedback to prevent rapid cycling between turn on and turn off.

12 Application Note 0 T IN00.MΩ N9 HEATE V 0Hz 0Ω V 0Hz µf 0V PTC TEMP. SENSO kω kω 0kΩ TEMP. SET N9 0kΩ CA09B.kΩ G MT MT kω 0.0µF kω kω NOTE: All esistors are /W. FIGUE. TEMPEATUE CONTOLLE Battery Charger egulator Circuit The circuit for battery charger regulator circuit using the CA09 is shown in Figure. This circuit accurately limits the peak output voltage to V, as established by the zener diode connected across terminals and. When the output voltage rises slightly above V, signal feedback through a 00kΩ resistor to terminal reduces the current drive supplied to the N0 pass transistor from terminal of the CA09. An incandescent lamp serves as the indicator of charging current flow. Adequate limiting provisions protect the circuit against damage under load short conditions. The advantage of the circuit over certain the types of regulator circuits is that the reference voltage supply doesn t drain the battery when the power supply is disconnected. This feature is important in portable service applications, such as in a trailer where a battery is kept oncharge when the trailer is parked and power is provided from an AC line. AC IN V TO V MS D D. D D D 00Ω 00kΩ 00kΩ MUALITES LAMP L0/0 0Ω /W Ω 0W N0 00Ω N9 CA09A 00kΩ 0.00µF V E OUT TO kω BATTEY V PEAK FIGUE 9. BATTEY CHAGE EGULATO CICUIT Ground Fault Interrupters (GFI) Ground fault interrupter systems are used to continuously monitor the balance of current between the high and neutral lines of power distribution networks. Power is interrupted whenever the unbalance exceeds a preset value (e.g., ma). An unbalance of current can occur then, for example, defective insulation in the high side of the line permits leakage of current to an earth ground. GFI systems can be used to reduce the danger of electrocution from accidental contact with high line because the unbalance caused by the leakage of current from the high line through a human body to ground results in an interruption of current flow. The CA09 is ideally suited for GFI applications because it can be operated from a single supply, has adequate sensitivity, and can drive a relay or thyristor directly to effect power interruption. Figure shows a typical GFI circuit. Vernier adjustment of the trip point is made by the TIP potentiometer. When the differential current sensor supplies a signal that exceeds the selected trippoint voltage level (e.g., 0mV), the CA09 is toggled on and terminal goes low to energize the circuit breaker trip coil. Under quiescent conditions, the entire circuit consumes approximately ma. The resistor, connected to one leg of the current sensor, provides current limiting to protect the CA09 against voltage spikes as large as 00V. Figure also shows the pertinent waveform for the GFI circuit. Because hazards of severe electrical shock are a potential danger to the individual user in the event of malfunctions in GFI apparatus, it is mandatory that the highest standard of good engineering practice be employed in designing equipment for this service. Every consideration in design and application must be given to the potentially serious consequences of component malfunction in such equipment. Use of reliability through redundancy concepts and so called failsafe features is encouraged.

13 Application Note 0 0V AC LINE HIGH kω SENSO MΩ 0kΩ 0.0µF kω CA09B 0kΩ W N00 0kΩ 0Ω G 00µF V LOAD MT MT E OUT LOW FIGUE 0. LINE OPEATED THYISTO FIING CICUIT CONTOLLED BY AC BIDGE SENSO 00mV ANGE K L C 0.0µF 0.µF TIP C K 00Ω.K K 00K DIFFEENTIAL CUENT SENSO POVIDES K 0mV SIGNAL ma OF UNBALANCE (TIP) CUENT NOTES:. All resistors in Ω, /W, 0%.. C selected for db point at 00Hz.. C = AC bypass. ma V V 0µA I ABC.MΩ CA09B 0µA I A 00Ω 0.00µF CICUIT BEAKE CONTOL SOLENOID I LOAD eferences For Harris documents available on the internet, see web site Harris AnswerFAX (0) 00. [] CA00 and CA00A Data Sheet, Harris Corporation, Semiconductor Communications Division, FN. [] AN Application Note, Harris Corporation, Semiconductor Communications Division, Applications of the CA00 and CA00A High Performance Operational Transconductance Amplifiers. [] AN0 Application Note, L. Kaplan and H. A. Wittlinger, Harris Corporation, Semiconductor Communications Division, An IC Operational Transconductance Amplifier (OTA) with Power Capability. Paper originally presented at the IEEE Chicago Springs Conference on Broadcast and TV eceivers, June 9. eprinted as AN0. [] CA0 Data Sheet, Harris Corporation, Semiconductor Communications Division, FN9. [] CA0 Data Sheet, Harris Corporation, Semiconductor Communications Division, FN.. Offset ADJ included in TIP.. Input impedance from to equals 00K.. With no input signal terminal (Output) at V. CICUIT TIPS ON POSITIVE PEAKS WILL SWITCH WITHIN. CYCLES VOLTAGE BETWEEN TEMINALS AND VOLTS 0mV TYPICAL VOLTAGE BETWEEN TEMINALS AND (ADJUSTABLE WITH TIP ) GOUND FAULT SIGNAL 0Hz t FIGUE. GOUND FAULT INTEUPTE (GFI) AND WAVEFOM PETINENT TO GOUND FAULT DETECTO