Switch control circuit diagram mcu

  
As shown in FIG TOPSwitch FZ chip switching power supply circuit diagram is controlled by the MCUs. The microcontroller can use inkjet printers, laser printers and other comput
Switch control circuit diagram mcu - schematic

er peripherals TOPSwitch FX constituted by a switching power supply control circuit shown in Fig. Switching power supply mainly composed TOPSwitch FX (IC1), optocoupler (IC2) components. The control circuit includes a microcontroller (MCU), two LTV817A linear optocoupler (IC3, IC4), push button switch SB. Signal is generated only when you press the SB is only valid when lifting signal does not work. The SB would not need anti-shake circuit, because the switching power supply soft start time (about 10ms) and the MCU initialization and reset delay time can play a role, you can avoid the time jitter interference when pressed SB; and only when the switch is pressed at least to achieve the above time, the switch to turn on the power by MCU. This will require the SB press in the end, instead of single click, to ensure power supply starter. After the completion of MCU initialization and reset detected IC3 sent to the start signal, and then go through the power lock switch IC4. Optocoupler IC3, IC4 of LED light tube and phototransistor, respectively LED3 and VT3, LED4 and VT4 representation. Now LED3 connected between the control terminal and the SB upper, VT3 connected to the logic input MCU. No current through LED3 under normal, IC3 does not work. Logic output MCU through isolation diodes and resistors R4 VD6 then positive LED4 of. VT4 is connected between the M, S end. M by itself end limiting function, it does not require additional VT4 limiting resistor. CM multifunctional end noise cancellation capacitor. When a user first press SB, VD4 conduction, M and S pole end through VD4 turned, TOPSwitch FX namely in three terminal mode, multi-function terminal (M) and switching frequency setting terminal (F) does not work, the current through LED3 on this point, VT3 give MCU start signal. If the power switch is initially in the OFF state (M-side floating) for the first time the power is turned on by pressing SB, + 5V output voltage UCC provides operating power supply voltage for the MCU. MCU orders after receiving a start signal VT4 conduction, switching power remains in the ON state, the normal output. When the user presses again on the issue of SB shutdown signal, MCU receives the signal after the implementation of the shutdown procedure, the ink jet printer head stop at a safe place. Once you perform the shutdown procedure, MCU will make it VT4 off the M terminal vacant, switching power shutdown mode, when TOPSwitch FX in a low power state, when UI 230VAC the chip consumes only 160mW. If the DVD is used when the power switch, the shutdown procedure and the data set state can be stored in the E2PROM, yet they are not lost even after power failure.




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