CN204732947U - A kind of charging control circuit for mobile phone - Google Patents

Abstract

The utility model discloses a kind of charging control circuit for mobile phone, comprise rectifier circuit, transformer, triode, feedback control circuit, the external civil power of input of rectifier circuit, the positive output end of rectifier circuit is held with the A of primary winding and is connected, the positive output end of rectifier circuit is also connected with the negative pole of the first voltage stabilizing didoe, the positive pole of the first voltage stabilizing didoe to be held with the B of primary winding by electric capacity and is connected, the positive output end of rectifier circuit is also connected with the base stage of triode by starting resistance, the collector electrode of triode is held with the B of primary winding and is connected, the emitter of triode is connected with the negative output terminal of rectifier circuit by resistance, transformer secondary output is around being output, the sampling winding of transformer is connected with the base stage of triode by feedback control circuit.The utility model circuit is simple, and easily realize, with low cost, volume is little, is convenient to be arranged in mobile phone, has a good application prospect.

Description

A charging control circuit for mobile phone

technical field

The utility model relates to a charging control circuit for a mobile phone, which belongs to the technical field of charging.

Background technique

At present, the charging control circuits used in mobile phones on the market are more complicated, use more electronic components, and have higher production costs, resulting in a larger circuit board size, which is not easy to install inside the mobile phone.

Utility model content

The purpose of this utility model is to overcome the existing charging control circuit applied to mobile phones. The circuit is more complicated, and the electronic components used are more, and the production cost is higher, resulting in a larger volume of the circuit board, which is not easy to install on inside the phone.

In order to achieve the above object, the technical solution adopted by the utility model is:

A charging control circuit for a mobile phone, characterized in that it includes a rectifier bridge circuit, a transformer T1, a triode Q1, and a feedback control circuit, the input end of the rectifier bridge circuit is externally connected to the mains, and the positive output end of the rectifier bridge circuit It is connected to the A terminal of the primary winding of the transformer T1, and the positive output terminal of the rectifier bridge circuit is also connected to the negative pole of the first voltage stabilizing diode D1, and the positive pole of the first voltage stabilizing diode D1 is connected to the primary side of the transformer T1 through a capacitor C1 The B terminal of the winding is connected, and the positive output terminal of the rectifier bridge circuit is also connected to the base of the triode Q1 through the starting resistor R1, and the collector of the triode Q1 is connected to the B terminal of the primary winding of the transformer T1. The emitter of the triode Q1 is connected to the negative output terminal of the rectifier bridge circuit through the resistor R2, one end of the secondary winding of the transformer T1 is also connected to the anode of the light-emitting diode D2, and the cathode of the Schottky diode VD is connected in series to limit the current Resistor R3, the rear end of the current-limiting resistor R3 is connected in parallel to a load RL, and the load RL is used as the output terminal of the charging control circuit, and the sampling winding of the transformer T1 is connected to the base of the transistor Q1 through the feedback control circuit, so The feedback control circuit includes a sampling current resistor R4, a second voltage stabilizing diode D2, a first diode D3, and a second diode D4. One end of the sampling winding of the transformer T1 is connected to one end of the sampling current resistor R4, the first The cathode of the diode D3 is connected, the anode of the first diode D3 is also connected to the other end of the sampling winding of the transformer T1 through the polarity capacitor C2, and the other end of the sampling current resistor R4 is connected to the triode through the capacitor C3 The base of Q1 is connected, the anode of the second zener diode D2 is connected with the anode of the first diode D3, the cathode of the second zener diode D2 is connected with the base of the transistor Q1, the The anode of the second diode D4 is connected to the other end of the sampling winding of the transformer T1, and the cathode of the second diode D4 is connected to the base of the transistor Q1.

The aforementioned charging control circuit for mobile phones is characterized in that: the transistor Q1 is an NPN transistor.

The aforementioned charging control circuit for a mobile phone is characterized in that a filter capacitor C4 is connected in parallel to both ends of the secondary winding of the transformer T1.

The aforementioned charging control circuit for mobile phones is characterized in that: the transformer T1 is a high-frequency switching transformer.

The aforementioned charging control circuit for mobile phones is characterized in that: the positive input end of the rectifier bridge circuit is connected in series with a fuse F1.

The aforementioned charging control circuit for mobile phones is characterized in that: the output voltage of the secondary winding of the transformer T1 is between 5V-6.2V.

The aforementioned charging control circuit for mobile phones is characterized in that: a light emitting diode D5 is connected in series at the rear end of the current limiting resistor R3.

The beneficial effects of the utility model are: the charging control circuit for mobile phones of the utility model is provided with a feedback control circuit, which can reduce the output voltage and prevent overcharging when the charging is saturated, the circuit is simple, and less electronic components are used. It is easy to implement, low in cost, small in size, convenient to be installed in mobile phones, and has good application prospects.

Description of drawings

Fig. 1 is a system block diagram of a charging control circuit for a mobile phone of the present invention.

Detailed ways

The utility model will be further described below in conjunction with the accompanying drawings of the description. The following examples are only used to illustrate the technical solution of the utility model more clearly, but not to limit the protection scope of the utility model.

As shown in Figure 1, the charging control circuit for mobile phone of the present utility model comprises rectifier bridge circuit, transformer T1, triode Q1, feedback control circuit, the input terminal of rectifier bridge circuit is externally connected to mains, and the positive output terminal of rectifier bridge circuit It is connected to the A terminal of the primary winding of the transformer T1, and the positive output terminal of the rectifier bridge circuit is also connected to the negative pole of the first Zener diode D1, and the positive pole of the first Zener diode D1 is connected to the B terminal of the primary winding of the transformer T1 through the capacitor C1 The positive output terminal of the rectifier bridge circuit is also connected to the base of the transistor Q1 through the starting resistor R1, the collector of the transistor Q1 is connected to the B terminal of the primary winding of the transformer T1, and the emitter of the transistor Q1 is connected to the rectifier through the resistor R2. The negative output terminal of the bridge circuit is connected, one end of the secondary winding of the transformer T1 is also connected with the positive pole of the light-emitting diode D2, the negative pole of the Schottky diode VD is connected in series with the current-limiting resistor R3, and the rear end of the current-limiting resistor R3 is connected in parallel as the load RL , the load RL is used as the output terminal of the charging control circuit, the sampling winding of the transformer T1 is connected with the base of the transistor Q1 through the feedback control circuit, the feedback control circuit includes the sampling current resistor R4, the second Zener diode D2, the first diode D3, the second diode D4, one end of the sampling winding of the transformer T1 is respectively connected to one end of the sampling current resistor R4 and the negative pole of the first diode D3, and the positive pole of the first diode D3 is also connected to the polarity capacitor C2 The other end of the sampling winding of the transformer T1 is connected, the other end of the sampling current resistor R4 is connected to the base of the triode Q1 through the capacitor C3, and the anode of the second Zener diode D2 is connected to the anode of the first diode D3 , the cathode of the second Zener diode D2 is connected to the base of the transistor Q1, the anode of the second diode D4 is connected to the other end of the sampling winding of the transformer T1, and the second diode D4 The negative pole is connected with the base of the transistor Q1.

The triode Q1 is an NPN triode, and the two ends of the secondary winding of the transformer T1 are also connected in parallel with a filter capacitor C4 to improve the stability of the output voltage so as to charge the battery in the mobile phone. The transformer T1 is a high-frequency switching transformer, and the iron core is a high-frequency The ferrite core has high resistivity to reduce eddy current and improve the conversion effect. Through the external load resistor RL, the output voltage is between 5V-6.2V, which is slightly higher than the 5V voltage for the battery in the mobile phone, which is convenient for power supply. The battery in the mobile phone is charged, and the positive input terminal of the rectifier bridge circuit is connected in series as a fuse F1 to prevent excessive current from burning out other electronic components.

A light emitting diode D5 is connected in series at the rear end of the current limiting resistor R3.

The charging control circuit for mobile phones of the utility model has the following working principles: mains power input, rectification by the rectifier bridge circuit, and then sent to the transformer T1 through the first voltage stabilizing diode D1, and the starting resistor R1 provides the emitter for starting the triode Q1. Current, when the transistor Q1 is in the cut-off state, the primary winding of the transformer T1 works normally, and outputs a voltage of 5V-6.2V to charge the battery in the mobile phone. When the battery in the mobile phone is fully charged, the voltage reaches above 5V, which is close to the output voltage of the transformer T1. When it reaches the highest value, the voltage on the sampling current resistor R4 of the feedback control circuit increases as the output of the transformer T1 increases, causing the triode Q1 to be turned on, the primary winding of the transformer T1 does not work, and no voltage output is performed. In this way, the feedback control is realized. Even if the charging is not unplugged, it is not actually charging, so it is easy to use, simple and reliable.

The charging control circuit for mobile phones of the utility model is provided with a feedback control circuit, which can reduce the output voltage and prevent overcharging when the charging is saturated. , easy to be installed in mobile phones, and has good application prospects.

The basic principles, main features and advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model The new model also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed utility model. The scope of protection required by the utility model is defined by the appended claims and their equivalents.

Claims (7)

1. A charge control circuit for mobile phone, characterized in that: comprise rectifier bridge circuit, transformer T1, triode Q1, feedback control circuit, the input terminal of described rectifier bridge circuit is externally connected to mains, the positive of described rectifier bridge circuit The output terminal is connected to the A terminal of the primary winding of the transformer T1, and the positive output terminal of the rectifier bridge circuit is also connected to the negative pole of the first voltage stabilizing diode D1, and the positive pole of the first voltage stabilizing diode D1 is connected to the transformer through the capacitor C1 The B terminal of the primary winding of T1 is connected, and the positive output terminal of the rectifier bridge circuit is also connected with the base of the transistor Q1 through the starting resistor R1, and the collector of the transistor Q1 is connected with the B terminal of the primary winding of the transformer T1, The emitter of the triode Q1 is connected to the negative output terminal of the rectifier bridge circuit through the resistor R2, one end of the secondary winding of the transformer T1 is also connected to the anode of the light-emitting diode D2, and the cathode of the Schottky diode VD is connected in series to limit the current Resistor R3, the rear end of the current-limiting resistor R3 is connected in parallel to a load RL, and the load RL is used as the output terminal of the charging control circuit, and the sampling winding of the transformer T1 is connected to the base of the transistor Q1 through the feedback control circuit, so The feedback control circuit includes a sampling current resistor R4, a second voltage stabilizing diode D2, a first diode D3, and a second diode D4. One end of the sampling winding of the transformer T1 is connected to one end of the sampling current resistor R4, the first The cathode of the diode D3 is connected, the anode of the first diode D3 is also connected to the other end of the sampling winding of the transformer T1 through the polarity capacitor C2, and the other end of the sampling current resistor R4 is connected to the triode through the capacitor C3 The base of Q1 is connected, the anode of the second zener diode D2 is connected with the anode of the first diode D3, the cathode of the second zener diode D2 is connected with the base of the transistor Q1, the The anode of the second diode D4 is connected to the other end of the sampling winding of the transformer T1, and the cathode of the second diode D4 is connected to the base of the transistor Q1. 2. A charging control circuit for a mobile phone according to claim 1, wherein the transistor Q1 is an NPN transistor. 3 . The charging control circuit for mobile phones according to claim 1 , wherein a filter capacitor C4 is connected in parallel with both ends of the secondary winding of the transformer T1 . 4. A charging control circuit for a mobile phone according to claim 1, wherein the transformer T1 is a high-frequency switching transformer. 5. The charging control circuit for mobile phone according to claim 1, characterized in that: the positive input terminal of the rectifier bridge circuit is connected in series as a fuse F1. 6. The charging control circuit for mobile phones according to claim 1, wherein the output voltage of the secondary winding of the transformer T1 is between 5V-6.2V. 7. A charging control circuit for a mobile phone according to claim 1, wherein a light emitting diode D5 is connected in series at the rear end of the current limiting resistor R3.