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Mobile phone travel charger circuit and working principle

Published on Mar 17 2011 // Electrical Circuits

The charger uses the RCC-type switching power supply, that is, oscillation suppression converter, PWM switching power supply it with a certain distinction. PWM Switching Power Supply by an independent sampling error amplifier and dc amplifier pulse width modulation system; and RCC-type switching power supply is composed by the regulator level switch, the control process is oscillating state and restrained. Because PWM-type switching power supply switch off is always cyclical, the system control just change the pulse width of each cycle, and RCC-type switching power supply control process and nonlinear continuous change, it has only two states: When the switch power supply output voltage exceeds rated value, the pulse controller output low, cut-off switch; When switching power supply output voltage is lower than the rated value, the pulse controller output high, the switch turns on. When the load current decreases, the filter capacitor discharge time is extended, the output voltage will not soon reduced, the switch is off until the output voltage down to the rated value, the switch will turn on again. Switch cut-off time depends on the size of the load current. The turn-on switch / cut-off by the switch from the output voltage level control sample. So the power supply, also known as non-cyclical switching power supply. 220V electricity by VD1 ~ VD4 V2 after the bridge rectifier to form a collector DC voltage of about 300V. V2 formed by the blocking oscillator transformer and switch. Boot, 300V DC voltage through the transformer primary collector added to V2, while the voltage by the startup resistor R2 is also the base for the V2 to provide a bias voltage. The positive feedback, V2 Ic increased rapidly and saturated at V2 into the cut-off period, the switch transformer secondary winding induced voltage generated by the VD7 turn to load the output of a DC voltage of about 9V. Switch the transformer feedback winding through VD5 the induced pulse rectifier, C1 filtering and oscillation pulses to generate a DC voltage proportional to. If this voltage exceeds the value of the regulator regulator VD17, VD17 will turn this negative rectified voltage V2 will be added to the base, it quickly closed. The deadline for V2 in inverse proportion to its output voltage. VD17′s turn / cut directly affected by the grid voltage and load resistance. The lower the supply voltage or load current increases, VD17 on-the shorter the time, V2 longer conduction time, whereas the higher grid voltage or load current smaller, VD5 higher voltage rectifier, VD17 conduction time longer, V2′s on-time shorter. V1 is the over-current protection tube, R5 is V2 Ie the sampling resistor. When V2 Ie is too large, R5 V1 on the conduction voltage drop, V2 off, can effectively eliminate the impact of the current boot instantly, while the control function of VD17 is a compensation. VD17 V2 to the voltage controlled oscillator sampling time, and V1 V2 is to control the oscillation of the current sampling time. If it was nickel-cadmium, nickel metal hydride battery, because there is a certain type of battery memory effect, need to discharge them from time to time. SW1 is a nickel-cadmium, nickel hydrogen, lithium-ion battery switch. SW1 baseline power and precision op amp LM324 ⑨ SL431 to provide two different precision reference source, the switch SW1. In a nickel-cadmium, nickel metal hydride battery is charging, LM324 ⑨ pin reference voltage of about 0.09V (no load); In a lithium-ion battery charging, LM324 9 pin reference voltage of about 0.08V (no load), which designed by these two types of cell-specific chemical characteristics of the decision. Press the SW2, V5 base was a low moment of the turn, the residual voltage of rechargeable pool the ec by V5 R17 on the pole in the discharge, while the discharge lamp VD14 lit. SW2 is pressed immediately after release, when the residual voltage of rechargeable pool by R16, R13 partial pressure, C9 V4 after filtering the base to provide a high level, V4 conduction, which is equivalent to short-circuit SW2. As the discharge time, rechargeable pool getting lower and lower residual voltage when the voltage on V4 base can not continue to turn while maintaining, V4 off, the discharge end, the charger into the charging status immediately. Because there is no memory effect of lithium, when the battery is less than 3V when it can not boot, the residual voltage through resistor R40, R41 partial pressure obtained 2.53V into the op amp’s inverting terminal 3, 5, 10 feet, the LM324 9 pin voltage the load is always 2.66V, so 8 pin output low, V3 conduction, +9 V voltage through V3 ec pole, VD8 to rechargeable batteries. IC1 d under the action of the capacitor C6, {14} is a pulse signal output pins, as IC1 8 pin is low, so VD12 is flashing to indicate the battery is charging, the corresponding capacity of 20%. As the charging time can be gradually increased the voltage charging pool. When R40, R41 is equal to the partial pressure value of about 2.58V, that IC1 3 When the foot is equal to 2.58V, IC1 2 After the partial pressure of the foot by the resistance was 2.57V, the output of its 1 feet high (due to the charge, IC1 9 pin voltage is always 2.66V, V6 conduction; whereas in no-load, IC1 9 pin is 0.08V, V6 deadline), VD10, VD11 lit, indicates a capacity corresponding to 40%, 60%. When R40, R41 value of the partial pressure of up to 2.63V, ie, IC1 5 foot equivalent 2.63V, their feet by the resistor divider 6 after that 2.63V, 7 pin output high, VD9 light, corresponding to the charge capacity 80%. IC1 10 only when the pin voltage is ≥ 2.66V, 8 pin before output high, VD13 light, corresponding to the charge capacity of 100%. Even VD13 lit, VD12 is still flashing, this means that the battery has not yet reached full saturation. Only IC1 8 pin voltage> 6.5V when, VD12 gradually extinguished, said the battery is fully charged to saturation. VD16 in the circuit from over-charge, over-current protection function, VD8 protection from reverse to avoid the power charger, the battery reverse discharge.

This paper describes a switch-type mobile phone charger works, for beginners to understand the specific switching power supply circuit and the charge control circuit makes sense, these articles are generally more by the readers, so the urge like the hands-on production, transformation friends, to record your experiences, give more good draft.
Chaolitong mobile phone travel charger for a Motorola 308,328,338 and 368 series of mobile phone battery. The charger has a nickel-cadmium, nickel hydrogen, lithium-ion battery switch, and has a discharge function. In 150 ~ 250V, 40mA AC mains input, can output 300 ± 50mA DC current. I work under the physical diagram plotted for reference.

Mobile phone travel charger circuit and working principle.

The charger uses the RCC-type switching power supply, that is, oscillation suppression converter, PWM switching power supply it with a certain distinction. PWM Switching Power Supply by an independent sampling error amplifier and dc amplifier pulse width modulation system; and RCC-type switching power supply is composed by the regulator level switch, the control process is oscillating state and restrained. Because PWM-type switching power supply switch off is always cyclical, the system control just change the pulse width of each cycle, and RCC-type switching power supply control process and nonlinear continuous change, it has only two states: When the switch power supply output voltage exceeds rated value, the pulse controller output low, cut-off switch; When switching power supply output voltage is lower than the rated value, the pulse controller output high, the switch turns on. When the load current decreases, the filter capacitor discharge time is extended, the output voltage will not soon reduced, the switch is off until the output voltage down to the rated value, the switch will turn on again. Switch cut-off time depends on the size of the load current. The turn-on switch / cut-off by the switch from the output voltage level control sample. So the power supply, also known as non-cyclical switching power supply.
220V electricity by VD1 ~ VD4 V2 after the bridge rectifier to form a collector DC voltage of about 300V. V2 formed by the blocking oscillator transformer and switch. Boot, 300V DC voltage through the transformer primary collector added to V2, while the voltage by the startup resistor R2 is also the base for the V2 to provide a bias voltage. The positive feedback, V2 Ic increased rapidly and saturated at V2 into the cut-off period, the switch transformer secondary winding induced voltage generated by the VD7 turn to load the output of a DC voltage of about 9V. Switch the transformer feedback winding through VD5 the induced pulse rectifier, C1 filtering and oscillation pulses to generate a DC voltage proportional to. If this voltage exceeds the value of the regulator regulator VD17, VD17 will turn this negative rectified voltage V2 will be added to the base, it quickly closed. The deadline for V2 in inverse proportion to its output voltage. VD17′s turn / cut directly affected by the grid voltage and load resistance. The lower the supply voltage or load current increases, VD17 on-the shorter the time, V2 longer conduction time, whereas the higher grid voltage or load current smaller, VD5 higher voltage rectifier, VD17 conduction time longer, V2′s on-time shorter. V1 is the over-current protection tube, R5 is V2 Ie the sampling resistor. When V2 Ie is too large, R5 V1 on the conduction voltage drop, V2 off, can effectively eliminate the impact of the current boot instantly, while the control function of VD17 is a compensation. VD17 V2 to the voltage controlled oscillator sampling time, and V1 V2 is to control the oscillation of the current sampling time.
If it was nickel-cadmium, nickel metal hydride battery, because there is a certain type of battery memory effect, need to discharge them from time to time. SW1 is a nickel-cadmium, nickel hydrogen, lithium-ion battery switch. SW1 baseline power and precision op amp LM324 9 SL431 to provide two different precision reference source, the switch SW1. In a nickel-cadmium, nickel metal hydride battery is charging, LM324 9 pin reference voltage of about 0.09V (no load); In a lithium-ion battery charging, LM324 9 pin reference voltage of about 0.08V (no load), which designed by these two types of cell-specific chemical characteristics of the decision. Press the SW2, V5 base was a low moment of the turn, the residual voltage of rechargeable pool the ec by V5 R17 on the pole in the discharge, while the discharge lamp VD14 lit. SW2 is pressed immediately after release, when the residual voltage of rechargeable pool by R16, R13 partial pressure, C9 V4 after filtering the base to provide a high level, V4 conduction, which is equivalent to short-circuit SW2. As the discharge time, rechargeable pool getting lower and lower residual voltage when the voltage on V4 base can not continue to turn while maintaining, V4 off, the discharge end, the charger into the charging status immediately.
Because there is no memory effect of lithium, when the battery is less than 3V when it can not boot, the residual voltage through resistor R40, R41 partial pressure obtained 2.53V into the op amp’s inverting terminal 3, 5, 10 feet, the LM324 9 pin voltage the load is always 2.66V, so 8 pin output low, V3 conduction, +9 V voltage through V3 ec pole, VD8 to rechargeable batteries. IC1 d under the action of the capacitor C6, {14} is a pulse signal output pins, as IC1 8 pin is low, so VD12 is flashing to indicate the battery is charging, the corresponding capacity of 20%. As the charging time can be gradually increased the voltage charging pool. When R40, R41 is equal to the partial pressure value of about 2.58V, that IC1 3 When the foot is equal to 2.58V, IC1 2 After the partial pressure of the foot by the resistance was 2.57V, the output of its 1 feet high (due to the charge, IC1 9 pin voltage is always 2.66V, V6 conduction; whereas in no-load, IC1 9 pin is 0.08V, V6 deadline), VD10, VD11 lit, indicates a capacity corresponding to 40%, 60%. When R40, R41 value of the partial pressure of up to 2.63V, ie, IC1 5 foot equivalent 2.63V, their feet by the resistor divider 6 after that 2.63V, 7 pin output high, VD9 light, corresponding to the charge capacity 80%. IC1 10 only when the pin voltage is ≥ 2.66V, 8 pin before output high, VD13 light, corresponding to the charge capacity of 100%. Even VD13 lit, VD12 is still flashing, this means that the battery has not yet reached full saturation. Only IC1 8 pin voltage> 6.5V when, VD12 gradually extinguished, said the battery is fully charged to saturation.
VD16 in the circuit from over-charge, over-current protection function, VD8 protection from reverse to avoid the power charger, the battery reverse discharge.