Phase-control IC with Current Feedback and. Overload. Protection

Transcription

1 Features Full-wave Current Sensing Mains Supply ariation Compensated Programmable Load-current Limitation with Over- and High-load Output ariable Soft Start oltage and Current Synchronization Automatic Retriggering Switchable Triggering Pulse Typically 125mA Internal Supply-voltage Monitoring Current Requirement 3mA Temperature-compensated Reference oltage Applications Advanced Motor Control Grinder Drilling Machine 1. Description The U2B is designed as a phase-control circuit in bipolar technology for motor control applications with load-current feedback and overload protection. It enables load-current detection and has a soft-start function as well as reference voltage output. Phase-control IC with Current Feedback and Overload Protection Figure 1-1. Block Diagram Overload 11 Limiting oltage Mains voltage compensation High load Supply voltage GND Automatic retriggering % 7% α max A 16 Current Phase control unit ϕ = f( 4 ) Output Full wave rectifier Programmable overload protection B Autostart C I max 9 oltage monitoring Atmel U2B 1 Load current Level shift Soft start Reference voltage

2 Figure 1-2. Block Diagram with External Circuit 23 ~ 1kΩ/2W D1 D3 R1 LED Load Limiting R2 33kΩ 15 oltage α max R 47kΩ Overload Mains voltage compensation High load S 11 Supply voltage GND C1 22µF + R3 16 Automatic retriggering Current Phase control unit ϕ = f( 4 ) Output Full wave rectifier % 7% Programmable overload protection α max A B Autostart C I max 9 Mode A B C S1 1Ω oltage monitoring Atmel U2B R4 3.3kΩ 1 Load current Level shift Soft start Reference voltage R6 (R6) = ±25m R5 C3 C4.1µF C5 R11 1MΩ + Overload threshold C2 4.7µF 3.3kΩ nf.15µf R14 R kω Load current compensation P1 5kΩ Set point R7 + C7 1µF 2

3 2. Pin Configuration Figure 2-1. Pinning DIP16/SO16 ISENSE 1 16 OUTPUT ISENSE 2 15 SYNC Cϕ 3 14 Rϕ CONTROL COMP 4 5 Atmel U2B OERLOAD HIGH LOAD ILOAD 6 11 S CSOFT 7 GND REF 9 MODE Table 2-1. Pin Description Pin Symbol Function 1 ISENSE Load current sensing 2 ISENSE Load current sensing 3 Cϕ Ramp voltage 4 CONTROL Control input 5 COMP Compensation output 6 ILOAD Load current limitation 7 CSOFT Soft start REF Reference voltage 9 MODE Mode selection GND Ground 11 S Supply voltage 12 HIGH LOAD High load indication 13 OERLOAD Overload indication 14 Rϕ Ramp current adjust 15 SYNC oltage synchronization 16 OUTPUT Trigger output 3

4 3. General Description 3.1 Mains Supply The Atmel U2B contains voltage limiting and can be connected with the mains supply via D 1 and R 1. Supply voltage between pin and pin 11 is smoothed by C 1. In the case of 6 7% of the overload threshold voltage, pins 11 and 12 are connected internally whereby sat 1.2. When 6 T7, the supply current flows across D 3. The series resistance R 1 can be calculated as follows: R mains Smax 1max = I tot where: mains Smax I tot I Smax I x = Mains supply voltage = Maximum supply voltage = Total current consumption = I Smax + I x = Maximum current consumption of the IC = Current consumption of the external components 3.2 oltage Monitoring When the voltage is built up, uncontrolled output pulses are avoided by internal voltage monitoring. Apart from that, all latches in the circuit (phase control, load limit regulation) are reset and the soft-start capacitor is short-circuited. This guarantees a specified start-up behavior each time the supply voltage is switched on or after short interruptions of the mains supply. Soft start is isnitiated after the supply voltage has been built up. This behavior guarantees a gentle start-up for the motor and automatically ensures the optimum run-up time. 3.3 Phase Control The function of the phase control is mainly identical to the well-known IC U211B. The phase angle of the trigger pulse is derived by comparing the ramp voltage 3, which is mains-synchronized by the voltage, with the set value on the control input, pin 4. The slope of the ramp is determined by Cϕ and its charging current Iϕ. The charging current can be varied using Rϕ at pin 14. The maximum phase angle, α max, can also be adjusted by using Rϕ (minimum current flow angle ϕmin), see Figure 7-1 on page. When the potential on pin 3 reaches the set point level of pin 4, a trigger pulse width, t p, is determined from the value of Cϕ (t p = 9µs/nF). At the same time, a latch is set with the output pulse as long as the automatic retriggering has not been activated. When this happens, no more pulses can be generated in that half cycle. The control input at pin 4 (with respect to pin ) has an active range from to -1. When 4 =, then the phase angle is at its maximum, α max, i.e., the current flow angle is minimum. The minimum phase angle, α min, is set with

5 3.4 Automatic Retriggering The current- circuit monitors the state of the triac after triggering by measuring the voltage drop at the triac gate. A current flow through the triac is recognized when the voltage drop exceeds a threshold level of typically 4m. If the triac is quenched within the relevant half-wave after triggering (for example owing to low load currents before or after the zero crossing of the current wave, or for commutator motors, owing to brush lifters), the automatic retriggering circuit ensures immediate retriggering, if necessary with a high repetition rate, t pp /t p, until the triac remains reliably triggered. 3.5 Current Synchronization Current synchronization fulfils two functions: Monitoring the current flow after triggering. In case the triac extinguishes again or does not switch on, automatic triggering is activated until the triggering is successful. Avoiding triggering due to an inductive load. In the case of inductive load operation, the current synchronization ensures that in the new half wave, no pulse will be enabled as long as there is a current available from the previous half wave, which flows from the opposite polarity to the actual supply voltage. The current synchronization as described above is a special feature of the Atmel U2B. The device evaluates the voltage at the pulse output between gate and reference electrode of the triac. As a result, no separate current synchronization input with specified series resistance is necessary. 3.6 oltage Synchronization with Mains oltage Compensation The voltage synchronizes the reference ramp with the mains supply voltage. At the same time, the mains-dependent input current at pin 15 is shaped and rectified internally. This current activates the automatic retriggering and at the same time is available at pin 5. By suitable dimensioning, it is possible to obtain the specified compensation effect. Automatic retriggering and mains voltage compensation are not activated until 15 - increases to. The resistance R sync. defines the width of the zero voltage cross over pulse, synchronization current, and hence the mains supply voltage compensation current. Figure 3-1. Suppression of Mains oltage Compensation and Automatic Retrigger Mains R x C62 Atmel U2B If the mains voltage compensation and the automatic retriggering are not required, both functions can be suppressed by limiting 15-7, see Figure

6 3.7 Load-current Compensation The circuit continuously measures the load current as a voltage drop at resistance R 6. The evaluation and use of both half waves results in a quick reaction to load-current change. Due to the voltage at resistance R 6, there is a difference between both input currents at pins 1 and 2. This difference controls the internal current source, whose positive current values are available at pins 5 and 6. The output current generated at pin 5 contains the difference from the load-current detection and from the mains voltage compensation, see Figure 1-2 on page 2. The efficient impedance of the set-point network generates a voltage at pin 4. A current, flowing out of pin 5 through R, modulates this voltage. An increase of mains voltage causes the increase of control angle α, an increase of load current results in a decrease in the control angle. This avoids a decrease in revolution by increasing the load as well as an increase of revolution by the increment of the mains supply voltage. 3. Load-current Limitation The total output load current is available at pin 6. It results in a voltage drop across R 11. When the potential of the load current reaches about 7% of the threshold value ( T7 ), i.e., about 4.35 at pin 6, it switches the high-load comparator and opens the switch between pins 11 and 12. By using an LED between these pins (11 and 12), a high-load indication can be realized. If the potential at pin 6 increases to about 6.2 (= T ), it switches the overload comparator. The result is programmable at pin 9 (operation mode) Mode Selection a) α max ( 9 = ) In this mode of operation, pin 13 switches to S (pin 11) and pin 6 to GND (pin ) after 6 has reached the threshold T. A soft-start capacitor is then shorted and the control angle is switched to α max. This position is maintained until the supply voltage is switched off. The motor can be started again with the soft-start function when the power is switched on again. As the overload condition switches pin 13 to pin 11, it is possible to use a smaller control angle, α max, by connecting a further resistance between pins 13 and 14. b) Auto start (pin 9 open), see Figure 7- on page 12 The circuit behaves as described above, with the exception that pin 6 is not connected to GND. If the value of 6 decreases to 25% of the threshold value ( T25 ), the circuit becomes active again with soft start. c) I max ( 9 = ), see Figure 7- on page 13 When 6 has reached the maximum overload threshold value (i.e., 6 = T ), pin 13 is switched to pin ( Ref ) through the resistance R (= 2kΩ) without the soft-start capacitor discharging at pin7. With this mode of operation, direct load-current control (I max ) is possible. 6

7 4. Absolute Maximum Ratings Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Reference point pin, unless otherwise specified. Parameters Pin Symbol alue Unit Sink current 11 I S 3 ma t µs 11 i s ma Synchronous currents 15 ±I sync 5 ma t µs 15 ±i sync 2 ma Phase Control Control voltage 4, I Input current 4 ±I I 5 µa Charging current 14 -I j max.5 ma Soft Start Input voltage 7, I Pulse Output Input voltage 16 + I I 2 11 Reference oltage Source Output current I ma t µs I 3 ma Load-current Sensing Input currents 1, 2 ±I i 1 ma Input voltages 5, 6 i Overload output 13 I L 1 ma High-load output 12 I L 3 ma t µs 12 I L ma Storage temperature range T stg 4 to +125 C Junction temperature range T j 125 C Ambient temperature range T amb to + C 5. Thermal Resistance Parameters Symbol alue Unit Junction ambient DIP16 SO16 on p.c. SO16 on ceramic R thja R thja R thja 12 1 K/W K/W K/W 7

8 6. Electrical Characteristics S = 13, T amb = 25 C, reference point pin, unless otherwise specified Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Supply 11 Supply-voltage limitation I S = 3.5mA I S = 3mA Current requirement S = 13. 1, 2, and 15 open Reference oltage Source Reference voltage I L = µa I L = 2.5mA I Temperature coefficient S = 2.5mA I S = µa oltage Monitoring 11 S S I S 3.6 ma Ref.6 Ref.4.9. TC Ref TC Ref Turn-on threshold - Son Phase Control Synchronization 15 Input current oltage sync. ±I sync.15 2 ma oltage limitation ±I L = 2mA ± sync Input current Current synchronization 16 ±I synci 3 3 µa Reference Ramp, see Figure 7-1 on page Charging current 14 I ϕ 1 µa Start voltage 3 max Temperature coefficient of start voltage 3 TC R.3 %/K Final voltage 3 min ( ± 2m) R ϕ - reference voltage I ϕ = µa 11, 14 Rϕ Temperature coefficient Pulse output current I ϕ = µa I ϕ = 1µA 16 = 1.2, Figure 7-2 on page 14 TC Rϕ.3 TC Rϕ %/K %/K %/K %/K 16 I ma Output pulse width Automatic Retriggering S = limit C 3 = 3.3nF, see Figure 7-3 on page 16 t p 3 µs Repetition rate I 15 15µA t pp t p Threshold voltage 16 ± I 2 6 m Soft Start, see Figure 7-4 and Figure 7-5 on page 11 7 Starting current 7 = I 5 15 µa Final current 7- = 1 I µa Discharge current +I.5 ma Output current 4 +I.2 2 ma Mains oltage Compensation, see Figure 7-6 on page /5 (1 and Transfer gain I 15 /I 5 2 open) G i Output offset current (R6) = 15 = 5 = ±I 2 µa

9 6. Electrical Characteristics (Continued) S = 13, T amb = 25 C, reference point pin, unless otherwise specified Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Load-current Detection, R 1 = R 2 = 3kΩ, 15 =, 5 = 6 =, see Figure 7-7 on page 12 Transfer gain I 5 /15m, I 6 /15m G I µa/m Output offset currents 5, 6, 7, I 3 6 µa Reference voltage I 1, I 2 = µa 1, 2 Ref 3 4 m Shunt voltage amplitude See Figure 1-2 on page 2 ± (R6) 25 m Load-current Limitation 6, 7, High load switching Overload switching Threshold T7 Figure 7-9 on page 12 Threshold T Figure 7- on page 13 Figure 7-11 on page 13 T T Restart switching Threshold T25 Figure 7- on page 12 T Input current Enquiry mode I i 1 µa Output impedance Switching mode R 2 4 kω Programming Input, see Figure 1-2 on page 2 9 Input voltage - auto-start 9 open Input current 9 = (a max ) 9 = (I max ) High Load Output, T7, see Figure 7-9 on page 12, I 12 = 3mA 11, 12 Saturation voltages 6- T7 6- T7 Overload Output, T, 9 = Open or 9 =, see Figure 7- on page 13 I 9 I sat.5 lim 7. Leakage current 6- T25, 13 = ( 11 +1) 13 I lkg.5 µa Saturation voltages 6- T, I 13 = µa 11, 12, 13 sat.1 Output current, maximum load 9 =, see Figure 7- on page I 13 1 ma Leakage current 6 T 13 I lkg 4 µa Output impedance Open collector, 6 T 13 R 2 4 kω Saturation voltage 6- T, I 13 = µa m µa µa 9

10 7. Diagrams Figure 7-1. Ramp Control 25 Phase Angle α ( ) nF nf 6.nF 4.7nF 3.3nF 2.2nF C ϕt = 1.5nF R ϕ (R ) (kω) Figure 7-2. Pulse Output 12 GT = -1.2 I GT (ma) R GT (Ω) Figure 7-3. Output Pulse Width 4 Δt p /ΔC ϕ = 9µs/nF 3 t p (µs) C ϕ = (nf)

11 Figure 7-4. Soft-start Charge Current 5 4 S = 13 6 = I 7 (µa) 3 2 Reference Point Pin () Figure 7-5. Soft-start Characteristic 12 1µF Reference Point Pin 2.2µF 4.7µF I 7 () 6 4 C ϕ = µf S = = t (s) Figure 7-6. Mains oltage Compensation 4 I 5 (µa) Pins 1 and 2 open S = I 15 (ma) Reference Point Pin 11

12 Figure 7-7. Load-current Detection = Ref = S = = = Reference Point Pin I 5 (µa) (R6) (m) Figure 7-. Restart Switching Auto Start Mode 2 16 S = -13 Pin 9 open Reference Points: 13 = pin, 6 = pin () 12 4 T25 T () Figure 7-9. High Load Switching (7%) I 12 = 3mA () 6 4 Reference Point Pin 2 T () 12

13 Figure 7-. Overload Switching 12 S = = () 6 4 Reference Points: 13 = pin, 6 = pin 2 T t (s) Figure Load Limitation 2 16 S = = Reference Points: 13 = pin, 6 = pin 13- () 12 4 T () Figure Power Dissipation of R 1 P v (W) R 1 (kω) 13

14 Figure Power Dissipation of R 1 According to Current Consumption M = 23 ~ P v (ma) I S (ma) Figure Maximum Resistance of R 1 R 1max (kω) 6 4 M = 23 ~ I S (ma) 14

15 Figure Application Circuit 23 ~ 1kΩ/2W D1 D3 L Load R2 33kΩ 15 R1 47kΩ 1MΩ R α max R9 α max Overload LED S 11 C1 22µF + Limiting oltage Mains voltage compensation High load Supply voltage GND R3 1Ω 16 Automatic retriggering Current Phase control unit ϕ = f( 4 ) % 7% Output B 9 Programmable Autostart S overload protection Full wave C I rectifier max oltage monitoring α max A Atmel U2B A B C R12 22kΩ R4 3.3kΩ 1 Load current Level shift Soft start Reference voltage T1 N R6 (R6) = ± 25m R5 3.3kΩ C3 nf Load current compensation C4.15µF R kω.1µf C5 R11 1MΩ R14 + Overload threshold P1 5kΩ Set point C2 4.7µF R7.2kΩ C7 D2 1N414 C6 + 1µF 1µF + R13 kω 15

16 . Ordering Information Extended Type Number Package Remarks U2B-MY DIP16 Tube, Pb-free U2B-MFPY SO16 Tube, Pb-free U2B-MFPG3Y SO16 Taped and reeled, Pb-free 9. Package Information Package DIP16 Dimensions in mm 2. max max.5 min max.39 max Alternative technical drawings according to DIN specifications 16

17 Package: SO 16 Dimensions in mm 9.9±.1 5±.2 3.7± ±.1 6± technical drawings according to DIN specifications 1 Pin 1 identity Drawing-No.: Issue: 1; Revision History Please note that the following page numbers referred to in this section refer to the specific revision mentioned, not to this document. Revision No. History 4766D-INDCO-3/ C-INDCO-4/ 4766B-INDCO-/5 Put datasheet in a new template Page 7: Abs.Max.Ratings table: Change in row Synchrosnous currents Page : El.Characteristics: Change in heading Put datasheet in the newest temlate Pb-free logo on page 1 deleted Figure 2-1 Pinning DIP16/SO16 on page 3 changed Put datasheet in the newest template Pb-free logo on page 1 added Section Ordering Information on page 16 changed 17

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