CN214069818U

CN214069818U - Security protection power supply circuit

Info

Publication number: CN214069818U
Application number: CN202120126989.6U
Authority: CN
Inventors: 王刚; 张枝兵
Original assignee: Shenzhen Gang Cheung Fair Electronics Co ltd
Current assignee: Shenzhen Gang Cheung Fair Electronics Co ltd
Priority date: 2021-01-18
Filing date: 2021-01-18
Publication date: 2021-08-27
Anticipated expiration: 2031-01-18

Abstract

The utility model provides a security protection power supply circuit, including current fuse F1, bridge stack BD1, NTC, common mode inductance LF1, CX1, MOV1, resistance R9, R10, R11, R12, electric capacity C1, transformer T1, resistance R4, resistance R4A, main control chip U1, resistance R3, resistance R3A, diode D2, resistance R5, electric capacity C2, resistance R8, resistance R7, electric capacity C3, electric capacity C5, resistance R6, resistance R7; the power grid L line is firstly connected with one end of an MOV1 and an NTC input end after passing through a current fuse F1, the NTC output end is connected with one end of CX1 and then connected with the input end of an LF1, and the output end of the LF1 is connected with the input end of a bridge stack BD 1; after the N line of the power grid is connected with the other end of the MOV1, the CX1 is connected with the other input end of the rectifier bridge stack BD1, so that the performance is stable and the consistency is good; and an IW7707C synchronous rectification scheme is adopted in the secondary stage, so that the heat generation is small and the efficiency is high.

Description

Security protection power supply circuit

[ technical field ]

The utility model relates to a security protection power technology field especially relates to a security protection power supply circuit that application effect is outstanding.

[ background art ]

The security protection power supply circuit is transited from the original fire cattle to the switch power supply due to power consumption, the switch power supply must meet the requirements of the original fire cattle on characteristics, interference, peak power, lightning resistance and the like, the platform compatibility is strong, the security protection power supply circuit can be applied to products with higher power through further design, and the security protection power supply circuit can be properly extended to telecommunication equipment for use.

The security protection working environment has high requirements for the stability of a power supply and the external interference, a linear power supply is adopted for the past, the linear power supply is switched to a switching power supply comprehensively due to the requirement for energy efficiency, the switching power supply is relatively easy to be interfered, meanwhile, an interference signal generated by the switching power supply can influence the working stability of a rear-stage circuit, and the switching is inevitable under the condition that the requirement for energy efficiency is more and more strict.

[ contents of utility model ]

For overcoming the problem that prior art exists, the utility model provides a security protection power supply circuit that application effect is outstanding.

The utility model provides a scheme for solve technical problem provides a security protection power supply circuit, including current fuse F1, bridge rectifier BD1, NTC, common mode inductance LF1, CX1, MOV1, resistance R9, R10, R11, R12, electric capacity C1, transformer T1, resistance R4, resistance R4A, main control chip U1, resistance R3, resistance R3A, diode D2, resistance R5, electric capacity C2, resistance R8, resistance R7, electric capacity C3, electric capacity C5, resistance R6, resistance R7; the power grid L line is firstly connected with one end of an MOV1 and an NTC input end after passing through a current fuse F1, the NTC output end is connected with one end of CX1 and then connected with the input end of an LF1, and the output end of the LF1 is connected with the input end of a bridge stack BD 1; the other end of the power grid N line is connected with the other input end of CX1 connected with the rectifier bridge stack BD1 after the other end of the MOV 1; the resistors R9, R10, R11 and R12 are combined in a series-parallel connection mode and then connected to two ends of CX1 in parallel to form a CX1 discharge circuit; the alternating current is rectified by the bridge stack BD1, filtered by the capacitor EC1 and then supplies power to the main coil of the transformer T1; the resistors R4 and R4A provide starting voltage for U1 when electrified; the 5 th pin and the 6 th pin of the main control chip U1 are connected with the main winding of the transformer T1 and are used for controlling the current and the time flowing through the main winding of the transformer T1; the resistors R3 and R3A are connected with the 4 th pin of the U1, and convert current signals flowing through the transformer T1 into voltage signals to be sent to the main control chip U1 for detection; one end of an auxiliary winding of the transformer T1 is connected with the positive end of a diode D2, the negative electrode of the auxiliary winding is connected with a resistor R5, the other end of the R5 is connected with a capacitor EC2 and a capacitor C2, and rectified voltage is filtered into direct-current voltage which is provided for the normal work of U1; the resistor R8 is connected with the resistor C5 in series and then connected to two ends of the resistor D2 in parallel to serve as a protection circuit of the resistor D2, and the EMI effect is improved; the auxiliary winding is connected with the 3 rd pin of the U1 through a network consisting of R6, R7 and C3 to provide a feedback voltage for the U1; the main control chip U1 adjusts the frequency and time of square wave output by the 5 th pin and the 6 th pin of the main control chip U1 according to signals provided by the 3 rd pin and the 4 th pin, ensures that the output obtains required voltage and current, and sets an over-power protection point of a power supply; the diode D1 is connected with the 5 th and 6 th pins of the main control chip U1 and the output of the primary winding of the transformer T1, the negative end of the diode D1 is connected with one end of a parallel resistor network formed by resistors R2 and R2A, the capacitor C1 is connected with a resistor R1 in parallel, one end of the capacitor C1 is connected with the positive end of the EC1, and the other end of the capacitor C1 is connected with a resistor network formed by R2 and R2A.

Preferably, the main control chip U1 is a power supply chip G1135 NSG.

Compared with the prior art, the single-panel PCB design of the security protection power supply circuit has the advantages that the transformer adopts a secondary extension structure, so that the manufacturing difficulty of the transformer is reduced on the basis of ensuring the safety distance; most of electronic parts adopt SMT technology, which is beneficial to batch production and improves production efficiency and quality; the master control power chip G1135NSG chip has stable performance and good consistency; and an IW7707C synchronous rectification scheme is adopted in the secondary stage, so that the heat generation is small and the efficiency is high.

[ description of the drawings ]

Fig. 1 is the utility model relates to a security protection power supply circuit's circuit connection schematic diagram.

[ detailed description of the invention ]

To make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the security power circuit 1 of the present invention includes a current fuse F1, a bridge rectifier BD1, NTC, a common mode inductor LF1, CX1, MOV1, a resistor R9, R10, R11, R12, a capacitor C1, a transformer T1, a resistor R4, a resistor R4A, a main control chip U1, a resistor R3, a resistor R3A, a diode D2, a resistor R5, a capacitor C2, a resistor R8, a resistor R7, a capacitor C3, a capacitor C5, a resistor R6, and a resistor R7.

After the alternating current is rectified and filtered, a controllable square wave is generated by a power supply chip G1135NSG, the square wave reduces higher voltage to safety voltage required by people through a transformer, the high voltage is rectified by a secondary synchronous rectification chip and filtered by an output electrolytic capacitor to form 12V direct current voltage, and the output voltage is connected to an output wire to supply power for equipment.

The core of the circuit is that an integrated PWM control chip and a power chip G1135NSG of an MOS power device generate controllable square waves, the square waves reduce the high voltage after alternating current rectification to required safe low voltage through the electromagnetic coupling of a primary winding and a secondary winding in a transformer, and a 12V direct current voltage is output after the synchronous rectification chip rectifies and filters; g1135NSG detects the voltage of the auxiliary winding according to the resistance voltage dividing network, controls the working state of the power supply according to the detected voltage signal and ensures that the power supply stably outputs a set voltage value; the current flowing through the power tube is detected through the resistor connected in series with the power tube, and when the voltage on the detection resistor reaches a set value of the chip, the current enters a protection state to ensure that the output power of the power supply is controlled within a safe range; the secondary adopts a synchronous rectification chip to effectively reduce the loss of the rectification circuit, effectively reduce the overall temperature of the product and ensure the working reliability of the product.

The power grid L line is connected with one end of an MOV1 and an NTC input end after passing through a current fuse F1, the NTC output end is connected with one end of CX1 and then connected with an input end of LF1, the output end of LF1 is connected with the input end of a bridge stack BD1, and the power grid N line is connected with the other end of the MOV1 and then connected with the other input end of CX1 and a rectifier bridge stack BD 1; r9, R10, R11 and R12 are combined in series and parallel and then connected in parallel to two ends of CX1 to be used as a CX1 discharge circuit; the alternating current is rectified by BD1, filtered by a capacitor EC1 and then supplies power to a main coil of a transformer T1; the R4 and the R4A provide starting voltage for the U1 when being electrified, the 5 th pin and the 6 th pin of the U1 can output a controllable square wave after the U1 starts to work, the 5 th pin and the 6 th pin of the U1 are connected with a main winding of a transformer T1 to control the current and the time flowing through the main winding of the transformer T1, and the R3 and the R3A are connected with the 4 th pin of the U1 to convert the current signal flowing through the transformer into a voltage signal to be detected by the U1; one end of an auxiliary winding of the transformer is connected with the positive end of D2, the negative electrode of the auxiliary winding of the transformer is connected with a resistor R5, the other end of R5 is connected with a capacitor EC2 and a capacitor C2, and rectified voltage is filtered into direct-current voltage to provide voltage for normal work of U1; r8 and C5 are connected in series and then are connected in parallel to two ends of D2 to serve as a protection circuit of D2 and improve EM I effect; the auxiliary winding is connected with the 3 rd pin of the U1 through a network consisting of R6, R7 and C3 to provide a feedback voltage for the U1; the U1 adjusts the frequency and time of square wave output by the 5 th and 6 th pins of the U1 according to signals provided by the 3 rd and 4 th pins, ensures that the output obtains required voltage and current, and sets an over-power protection point of a power supply; the diode D1 is connected with the 5 th and 6 th pins of the chip U1 and the output of the primary winding of the transformer T1, the negative end of the diode D1 is connected with one end of a parallel resistor network formed by R2 and R2A, the capacitor C1 is connected with the resistor R1 in parallel, one end of the capacitor C1 is connected with the positive end of the EC1, and the other end of the capacitor C1 is connected with the resistor network formed by R2 and R2A, so that a peak absorption loop is formed, and the working safety of the chip U1 is guaranteed.

The positive end of the secondary winding of the transformer T1 is connected with the 1 st, 2 nd and 3 rd pins of U2, the 5 th, 6 th, 7 th and 8 th pins of U2 are connected with the positive ends of EC3 and EC4 and then connected with one input end of LF2, the negative electrode of the output of the transformer is connected with the negative electrodes of EC3 and EC4 and then connected with the other input end of LF2, and the output of LF2 is respectively connected with the positive electrode and the negative electrode of the output line for external power supply; r14 and C7 are connected in parallel and then are respectively connected between the 3 rd pin and the 4 th pin of U2 to provide working voltage for U2; the R15 is connected in parallel with the two ends of the EC3 to be used as a power supply output load, so that the working stability of the power supply under light load is ensured.

One end of CY1 is connected with the positive pole of EC1, and the other end is connected with the negative pole of secondary output, and is used as a low-resistance path of power switch noise.

Compared with the prior art, the single-panel PCB design of the security protection power supply circuit 1 has the advantages that the transformer adopts a secondary extension structure, so that the manufacturing difficulty of the transformer is reduced on the basis of ensuring the safety distance; most of electronic parts adopt SMT technology, which is beneficial to batch production and improves production efficiency and quality; the master control power chip G1135NSG chip has stable performance and good consistency; and an IW7707C synchronous rectification scheme is adopted in the secondary stage, so that the heat generation is small and the efficiency is high.

The innovation points are as follows:

1. the project adopts a chip scheme of a PSR integrated power device, so that the cost performance is high, the efficiency is high, and the standby power consumption is low.

2. The main control IC, the resistor, the capacitor, the secondary synchronous rectification MOS and the IC adopt the SMT process except for the transformer and the capacitor fuse, so that the production efficiency is improved, and the consistency of the production quality is ensured.

3. The voltage and the current of the G1135NSG chip are detected simultaneously, so that the stability of the output voltage is ensured, and the output power of the power supply can be controlled.

4. And the secondary output adopts a synchronous rectification scheme, so that the efficiency is high.

5. The input end is connected with the piezoresistor, so that the damage of lightning stroke to the power supply and the rear-stage equipment is effectively prevented, and meanwhile, the NTC resistor is added, so that the input impact current is effectively reduced, and the reliability of the power supply is improved.

The above-mentioned embodiments of the present invention do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The utility model provides a security protection power supply circuit which characterized in that: the current fuse comprises a current fuse F1, a bridge stack BD1, an NTC, a common mode inductor LF1, a CX1, an MOV1, a resistor R9, a resistor R10, an R11, an R12, a capacitor C1, a transformer T1, a resistor R4, a resistor R4A, a main control chip U1, a resistor R3, a resistor R3A, a diode D2, a resistor R5, a capacitor C2, a resistor R8, a resistor R7, a capacitor C3, a capacitor C5, a resistor R6 and a resistor R7; the power grid L line is firstly connected with one end of an MOV1 and an NTC input end after passing through a current fuse F1, the NTC output end is connected with one end of CX1 and then connected with the input end of an LF1, and the output end of the LF1 is connected with the input end of a bridge stack BD 1; the other end of the power grid N line is connected with the other input end of CX1 connected with the rectifier bridge stack BD1 after the other end of the MOV 1; the resistors R9, R10, R11 and R12 are combined in a series-parallel connection mode and then connected to two ends of CX1 in parallel to form a CX1 discharge circuit; the alternating current is rectified by the bridge stack BD1, filtered by the capacitor EC1 and then supplies power to the main coil of the transformer T1; the resistors R4 and R4A provide starting voltage for U1 when electrified; the 5 th pin and the 6 th pin of the main control chip U1 are connected with the main winding of the transformer T1 and are used for controlling the current and the time flowing through the main winding of the transformer T1; the resistors R3 and R3A are connected with the 4 th pin of the U1, and convert current signals flowing through the transformer T1 into voltage signals to be sent to the main control chip U1 for detection; one end of an auxiliary winding of the transformer T1 is connected with the positive end of a diode D2, the negative electrode of the auxiliary winding is connected with a resistor R5, the other end of the R5 is connected with a capacitor EC2 and a capacitor C2, and rectified voltage is filtered into direct-current voltage which is provided for the normal work of U1; the resistor R8 is connected with the resistor C5 in series and then connected to two ends of the D2 in parallel; the auxiliary winding is connected with the 3 rd pin of the U1 through a network consisting of R6, R7 and C3 to provide a feedback voltage for the U1; the main control chip U1 adjusts the frequency and time of square wave output by the 5 th pin and the 6 th pin of the main control chip U1 according to signals provided by the 3 rd pin and the 4 th pin, ensures that the output obtains required voltage and current, and sets an over-power protection point of a power supply; the diode D1 is connected with the 5 th and 6 th pins of the main control chip U1 and the output of the primary winding of the transformer T1, the negative end of the diode D1 is connected with one end of a parallel resistor network formed by resistors R2 and R2A, the capacitor C1 is connected with a resistor R1 in parallel, one end of the capacitor C1 is connected with the positive end of the EC1, and the other end of the capacitor C1 is connected with a resistor network formed by R2 and R2A.

2. The security power supply circuit of claim 1, wherein: the main control chip U1 is a power chip G1135 NSG.