Pulse-Width-Modulation Control Circuits

Transcription

1 FEATURES Complete PWM Power Control Circuitry Uncommitted Outputs for 200 Sink or Source Current Output Control Selects SingleEnded or PushPull Operation Internal Circuitry Prohibits Double Pulse at Either Output ariable DeadTime Provides Control over Total Range Internal Regulator Provides a Stable 5 Reference Supply,5% Circuit Architecture Allows Easy Synchronization Moisture Sensitivity Level 3 Error AMP NONIN INPUT IN INPUT FEEDBACK DEADTIME CT RT GND SOP6/DIP6 (TOP IEW) NONIN INPUT IN INPUT REF OUT OUTPUT cc C2 E2 Error AMP 2 C 8 9 E DESCRIPTION The incorporate on a single monolithic chip all the functions required in the construction of a pulsewidthmodulation control, these devices offer the systems engineer the flexibility to tailor the power supply control circuitry to his application. The contains an error amplifier, an onchip adjustable oscillator, a deadtime control comparator, pulsesteering control flipflop, a 5volt, 5% precision regulator, and outputcontrol circuit. ORDERING INFORMATION Device Package The error amplifier exhibits a commonmode voltage range from 0.3 volts to cc 2 volts. The deadtime control comparator has a fixed offset that provides approximately 5% dead time when externally altered. The onchip oscillator may be bypassed by terminating R T (pin 6) to the reference output and providing a sawtooth in put to CT (pin 5), or it may be used to drive the common circuits in synchronous multiplerail power supplies. The uncommited output transistors provide either commonemitter or emitterfollower output capability. Each Device provides for pushpull or singleended output operation, which may be selected through the outputcontrol funct ion. The architecture of these devices prohibits the possibility of either output being pulsed twice during push pull operation. Functional Block Diagram D GD (Halogen Free) N SOP6 6 DIP R T C T OSCILLATOR OUTPUT CONTROL Q C DEAD TIME 0. DEADTIME CONTROL COMPARATOR C E CONTROL Q2 C2 E2 PWM COMPARATOR PULSESTEERING FLIPFLOP ERROR AMPLIFIER NONINERTING INPUT INERTING INPUT cc NONINERTING INPUT ERROR AMPLIFIER 2 FEEDBACK REFERENCE ref INERTING INPUT GND / 7

2 Parameter measurement information TEST CIRCUIT FIGURE. OPERATIONAL TEST CIRCUIT AND WAEFORMS 2 / 7

3 AMPLIFIER UNDER TEST FEEDBACK TERMINAL ref OTHER AMPLIFIER FIGURE 2. AMPLIFIER CHARACTERISTICS 5 (EACH OUTPUT CIRCUIT) 68 Ω 2 W OUTPUT t f t r C L =5pF (Includes probe and jig capacitance) 0% 0% TEST CIRCUIT OUTPUT OLTAGE WAEFORM FIGURE 3. COMMONEMITTER CONFIGURATION (EACH OUTPUT CIRCUIT) 5 68 Ω 2 W 0% 0% C L =5pF (Includes probe and jig capacitance) t r t f TEST CIRCUIT OUTPUT OLTAGE WAEFORM FIGURE 4. EMITTERFOLLOWER CONFIGURATION 3 / 7

4 ABSOLUTE MAXIMUM RATINGS OER OPERATING FREEAIR TEMPERATURE RANGE Rating alue Supply voltage, cc 4 Amplifier input voltage cc 0.3 Collector output voltage 4 Collector output current 250 Operating freeair temperature range 40 to 25 Storage temperature range 65 to 50 Lead temperature,6 mm from case for 0 seconds 260 o C RECOMMENDED OPERATING CONDITIONS Parameter alue MIN MAX Supply voltage, cc 7 40 Amplifier input voltage, i 0.3 cc 2 Collector output voltage, o 40 Collector output current (each transistor) 200 Current into feedback terminal 0.3 Timing capacitor, C T nf Timing resistor, R T KΩ Oscillator frequency 300 KHz Operating freeair temperature, T A o C Electrical characteristics over recommended operatng freeair temperature range, cc=5, f= 0 khz(unless otherwise noted). alue Parameter Test Conditions* MIN TYP** MAX Output voltage (ref) lo = Input regulation cc = 7 to Output regulation Io = to 0 Output voltage change with temperature T A = MIN to MAX 0.2 Shortcircuit output current*** ref = m % Oscillator section (See Figure ) Frequency Parameter Standard deviation of frequency**** Frequency change with voltage cc=7 to 40, T A =25 0. Frequency change with temperature**** Test Conditions* C T =0.0μF, R T =2KΩ All values of cc, C T,R T, and T A constant C T =0.0μF, R T =2KΩ, T A = MIN to MAX alue MIN TYP** MAX 0 KHz 0 % 4 / 7

5 Electrical characteristics over recommended operating freeair temperature range, cc=5, f=0khz (unless otherwise noted) Amplifier section (See Figure 2) Openloop voltage amplification SYMBOL TEST CONDITIONS MIN. TYP**. MAX. UNIT Input offset voltage o(pin 3)= m Input offset current o(pin 3)= na Input bias current o(pin 3)= Commonmode input voltage range cc = 7 to ~2 o=3, R L =2KΩ, o=0.5~3.5 Commonmode rejection ratio o= 40, T A = 25 o C 65 Output source current (pin 3) ID =5m~5, ( pin3 )= ygain bandwidth o=0.5~3.5, R L =2KΩ 800 μa 80 db Output sink current (pin 3) ID =5m~5, ( pin3 )= db khz *For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. ** All typical values except for parameter changes with temperature are at TA =25 oc *** Duration of the shortcircuit should not exceed one second. **** Standard deviation is a measure of the statistical distribution about the mean as derived from the formula. ***** Temperature coefficient of timing capacitor and timing resistor not taken into account. Output section PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT Collector offstate current CE =40, cc= Emitter offstate current CC = C =40, E =0 00 μa Commonemitter E =0, I C = Emitterfollower c=5, I E = Output control input current I =ref 3.5 Collectoremitter saturation voltage Deadtime controlsection (See Figure ) PARAMETER TEST CONDITIONS MIN. TYP* Input bias current(pin4) I =0 to Maximum duty cycle, each output I (pin 4) =0, C T =0.uF, R T =2KΩ 45 Input threshold voltage(pin 4) Zero duty cycle 3 Maximum duty cycle 0 MAX. UNIT 0 μa % 3.3 PMW comparator section (See Figure ) PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT Input threshold voltage (pin3) Zero duty cycle Input sink current (pin 3) (pin3) = Total device PARAMETER TEST CONDITIONS MIN. TYP* MAX. Pin 6 at ref, all other inputs CC =5 6 0 Standby supply current and outputs open CC = Average supply current I (pin 4)= UNIT 5 / 7

6 SUPPLY CURRENT Icc () SATURATION OLTAGE CE (sat) () SATURATION OLTAGE CE (sat) () OSCILLATOR FREQUENCY t osc (Hz) OPENLOOP OLTAGE GAIN A OL (db) EXCESS PHASE (DEGREES) PulseWidthModulation Control Circuits Switching characteristics, T A = 25 o C PARAMETER TEST CONDITIONS MIN. TYP* MAX. UNIT Output voltage rise time Commonemitter configuration Output voltage fall time Output voltage rise time Emitterfollower configuration ns Output voltage fall time * All typical values except for temperature coefficient are at T A = 25 o C t osc R T cc=5 O=3.0 RL=2.0 kω uF k uF k uF k 5.0 k 20 k TIMING RESISTANCE R T (Ω) k 0k 00k.0M FREQUENCY f(hz) CE(sat) I C CE I E COLLECTOR CURRENT I c EMITTER CURRENT I E () 0 I CC CC SUPPLY OLTAGE cc / 7

7 REISION NOTICE The description in this datasheet can be revised without any notice to describe its electrical characteristics proper 7 / 7