CAR CHARGER Works
CAR CHARGER works
The CAR CHARGER uses RCC-type switching power supply circuit, that is, oscillation suppression converter, and PWM-type switching power supply has some differences. PWM switching power supply by the independent sampling error amplifier and DC amplifier pulse width modulation system; and RCC-type switching power supply is only composed of voltage regulator level switch, the control process for the oscillation state and suppression state. Since the switch in the PWM switching power supply is always on and off, the system control only changes the pulse width of each cycle, and the control process of the RCC type switching power supply does not change linearly. It has only two states: when the switching power supply When the output voltage exceeds the rated value, the pulse controller output low, switch off; when the switching power supply output voltage is lower than the rated value, the pulse controller output high, CAR CHARGER switch tube conduction. When the load current decreases, the filter capacitor discharge time is extended, the output voltage will not be reduced quickly, the switch is in the cut-off state, until the output voltage drops below the rated value, the switch will turn on again. The cut-off time of the switch depends on the size of the load current. The on / off of the switch is controlled by the level switch from the output voltage. CAR CHARGER So this power supply, also known as non-periodic switching power supply.
AC 220V electricity by VD1 ~ VD4 bridge rectifier in the V2 collector on the formation of a 300V or so DC voltage. The intermittent oscillator is composed of V2 and switching transformers. After starting, 300V DC voltage through the transformer primary added to the V2 collector, while the voltage is also starting resistor R2 for the base of V2 to provide a bias voltage. As a result of the positive feedback, CAR CHARGER V2 Ic rises rapidly and saturates. During the V2 entry deadline, the induced voltage generated by the secondary winding of the switching transformer causes the VD7 to turn on and output a DC voltage of about 9V to the load. The feedback pulse generated by the feedback winding of the switching transformer is rectified by VD5, and the C1 filter produces a DC voltage proportional to the number of oscillating pulses. If this voltage exceeds the regulator VD17 regulator value, VD17 will turn on, the negative rectifier voltage will be added to the base of V2, so that it quickly cut off. The cut-off time of V2 is inversely proportional to its output voltage. VD17 on / off directly affected by the grid voltage and load. The lower the grid voltage or the higher the load current, the shorter the conduction time of VD17, the longer the conduction time of V2, CAR CHARGER and vice versa. The higher the grid voltage or the smaller the load current, the higher the VD5 rectified voltage, the VD17 turn-on time The longer the V2, the shorter the conduction time. V1 is overcurrent protection tube, R5 is V2 Ie sampling resistor. When V2 Ie is too large, R5 voltage drop on the V1 conduction, V2 cut off, can effectively eliminate the instantaneous impact current, while the VD17 control function is also a compensation. VD17 is used to control the oscillation time of V2 by voltage sampling, and V1 is the current sampling to control the V2 oscillation time.
If it is for the nickel-cadmium, CAR CHARGER nickel-metal hydride battery charging, because of this type of battery there is a certain memory effect, from time to time to discharge it. SW1 is nickel-cadmium, nickel-hydrogen, lithium-ion battery charging switch. SW1 and precision reference power supply SL431 for the op amp LM324 ⑨ provides two different precision reference source, SW1 switch. When charging the nickel-cadmium and nickel-metal hydride batteries, the reference voltage of the LM324 pin is about 0.09V (no load). When charging the lithium-ion battery, the reference voltage of the LM324 pin is about 0.08V (no load) The design is determined by the chemical properties of the two types of cells. Press the SW2, V5 base moment is a low level and conduction, rechargeable battery on the residual voltage through the V5's ec pole in the R17 discharge, CAR CHARGER while the discharge indicator VD14 light. After the release of SW2 will be released immediately, then the residual voltage on the rechargeable battery through the R16, R13 partial pressure, C9 filter for the V4 base to provide a high level, V4 conduction, which is equivalent to shorted SW2. With the extension of the discharge time, the residual voltage on the rechargeable battery is getting lower and lower. When the voltage on the base of V4 can not maintain its continuity, CAR CHARGER V4 is turned off and the discharge is terminated. The vehicle charger is turned into the charging state.