CN201674402U

CN201674402U - Switch power circuit

Info

Publication number: CN201674402U
Application number: CN2010201872809U
Authority: CN
Inventors: 博跟凯
Original assignee: Greenway Technology (Xiamen) Ltd
Current assignee: Pioneer automation (Xiamen) Co., Ltd.
Priority date: 2010-05-07
Filing date: 2010-05-07
Publication date: 2010-12-15
Anticipated expiration: 2020-05-07

Abstract

The utility model relates to an electronic circuit of a switch power supply. The technical scheme of the switch power circuit includes that an alternating current input end is connected to a transformer main end through an EMC filter and rectifying filter unit and a conversion circuit unit which are in serial connection, a transformer secondary end is connected to an output rectifying filter unit and a 36-V direct current output unit, the EMC filter and rectifying unit is further connected to an overload protection and main control circuit unit, output of the EMC filter and rectifying unit is connected to the conversion circuit unit, the overload protection and main control circuit unit is connected to an overload detection line and a load adjusting feedback unit through a photoelectric coupler, the overload detection line and the load adjusting feedback unit are connected to the output rectifying filter unit, the 36-V output unit is further connected to a 12-V output unit, and the 12-V output direct current output unit is further connected to a 3-V output unit. The switch power circuit adopts an integrated circuit chip, substantially reduces occupation of peripheral components on a PCB board, and is more integrally simplified.

Description

A kind of switching power circuit

Technical field

The utility model relates to electronic circuit field, relates in particular to the electronic circuit of Switching Power Supply.

Background technology

Switching power circuit is the time ratio that utilizes modern power electronics technology control switch pipe to turn on and off, and keeps a kind of power supply of regulated output voltage.Have in the existing switching circuit and adopt logic gates to add what the peripheral circuit overlap joint formed; poor reliability; element coherence request height; peripheral cell quantity is many, problems such as protective circuit parameter consistency difference, and original circuit does not have design power factor correcting pfc circuit; power factor correction relies on passive mode to proofread and correct; power factor is not high, and the low-frequency ripple coefficient is bigger, and can be coupled to secondary side by high frequency transformer.In addition, existing switching circuit does not possess the no-load power consumption controlled function, and its secondary side rectification circuit adopts traditional Schottky diode rectification circuit, have certain power consumption during big electric current, circuit heating is serious, influences the reliability of long-term work, and the reduction that can be affected of power supply overall efficiency.

The utility model content

At the problems referred to above, the utility model proposes a kind of improved switching power circuit, not only overcome above-mentioned various deficiencies, and adopted integrated circuit (IC) chip, significantly reduce peripheral component to the taking of pcb board, integrated circuit is more succinct.

The technical solution of the utility model is:

Switching power circuit of the present utility model is: ac input end is held to the transformer master through the EMC filtering of series connection and rectification filtering unit and conversion circuit unit; the secondary end of transformer connects output rectification filtering unit and 36V direct current output unit; described EMC filtering and rectification filtering unit output also are connected to overload protection and main control circuit unit; its output is connected in described conversion circuit unit; described overload protection and main control circuit unit are adjusted feedback unit through a photoelectrical coupler to overload detection circuit and load; this overload detection circuit and load are adjusted feedback unit and are connected to described output rectification filtering unit; described 36V output unit also is connected in the 12V output unit, and described 12V direct current output unit also is connected in the 3V output unit.

Further; described overload protection and main control circuit unit are made of TEA1530AT chip and the peripheral resistance capacitance that connects; its the 8th pin is connected in the output of the filter inductor of above-mentioned EMC filtering and rectification filtering unit; the 6th pin is connected in the control utmost point of a power switch pipe, and this power switch pipe is serially connected with between the coil and ground of transformer master end.

Further, described 12V output unit is to be made of LM2596S-12 chip and peripheral resistance, electric capacity and inductance, this resistance is connected in the Vin end of LM2596S-12 chip, electric capacity is connected between Vin end and the gnd end, inductance is connected in the out end output of LM2596S-12 chip, and electric capacity is connected between inductance output and the gnd end.

Further, described 3V output unit is to be made of LP2985IM5-X3.3 chip and peripheral electric capacity, this electric capacity is connected between the bypas end and gnd end of LP2985IM5-X3.3 chip, and this electric capacity is connected between the out end and gnd end of LP2985IM5-X3.3 chip.

The utility model adopts as above technical scheme, has following advantage:

A. main control chip is integrated in PFC and control circuit on the chip, significantly reduces peripheral component minimizing PCB and takies, and reduces element and can cut down finished cost and the effective quality control risk that reduces.

B. the pfc circuit that adds APFC and select for use control IC to integrate, the secondary side rectification circuit adopts up-to-date synchronous rectification scheme, can when maximum is exported, reduce the useless power consumption of 2-3W, on the Circuit theory can so that power factor bring up to more than 0.95.And under the situation of little amplitude increase primary side filter capacitor, can effectively reduce the low-frequency ripple coefficient of primary side, reduce low-frequency ripple and be coupled to secondary side, thereby make the ripple coefficient of secondary side be minimized.

C. the stand-by power consumption of power circuit can be dropped to low-down level.

D. circuit reduces the quantity and the capacity of circuit electrochemical capacitor as much as possible, so that use surface mount elements to substitute original electrochemical capacitor as far as possible.

Description of drawings

Fig. 1 is an electrical principle block diagram of the present utility model;

Fig. 2 is circuit theory diagrams of the present utility model.

Embodiment

Now with embodiment the utility model is further specified in conjunction with the accompanying drawings.

Consult shown in Figure 1; switching power circuit of the present utility model is: ac input end is held to the transformer master through the EMC filtering of series connection and rectification filtering unit 1 and conversion circuit unit 2; the secondary end of transformer connects output rectification filtering unit 4 and 36V direct current output unit 61; described EMC filtering and rectification filtering unit 1 output also are connected to overload protection and main control circuit unit 3; its output is connected in described conversion circuit unit 2; described overload protection and main control circuit unit 3 are adjusted feedback unit 5 through a photoelectrical coupler to overload detection circuit and load; this overload detection circuit and load are adjusted feedback unit 5 and are connected to described output rectification filtering unit 4; described 36V output unit 61 also is connected in 12V output unit 62, and described 12V direct current output unit 62 also is connected in 3V output unit 63.

Consult shown in Figure 2; described overload protection and main control circuit unit 3 are made of TEA1530AT chip U1 and the peripheral resistance capacitance that connects; its the 8th pin is connected in the output of the filter inductor LF1 of above-mentioned EMC filtering and rectification filtering unit 1; the 6th pin is connected in the control utmost point of a power switch pipe Q1, and this power switch pipe Q1 is serially connected with between the coil and ground of transformer master end.This TEA1530AT chip U1 is integrated PFC and power control circuit function because integrated level is high, only need the outer member of minute quantity, can realize the power supply design of high performance-price ratio.The quasi-resonance operation can be realized under the high power situation, the frequency reducing operation can be realized under the low-power consumption situation.

Described 12V output unit 62 is to be made of LM2596S-12 chip U2 and peripheral resistance R 24, electric capacity E9, E10 and inductance L 3, this resistance R 24 is connected in the Vin end of LM2596S-12 chip U2, electric capacity E9 is connected between Vin end and the gnd end, inductance L 3 is connected in the out end output of LM2596S-12 chip U2, and electric capacity E10 is connected between inductance L 3 outputs and the gnd end.The highest power supply conversion efficiency of this LM2596S-12 chip U2 reaches 96%, and the internal fixation frequency of oscillation can reduce inductance value reduction PCB area and take up to 260kHz.The peripheral circuit part is few, and output current is up to 1A.The input of wide voltage input ceiling voltage reaches 40V.

Described 3V output unit 63 is to be made of LP2985IM5-X3.3 chip U3 and peripheral capacitor C 10, E11, this capacitor C 10 is connected between the bypas end and gnd end of LP2985IM5-X3.3 chip U3, and this electric capacity E11 is connected between the out end and gnd end of LP2985IM5-X3.3 chip U3.

Although specifically show and introduced the utility model in conjunction with preferred embodiment; but the those skilled in the art should be understood that; in the spirit and scope of the present utility model that do not break away from appended claims and limited; can make various variations to the utility model in the form and details, be protection range of the present utility model.

Claims

1. switching power circuit; it is characterized in that: ac input end is held to the transformer master through the EMC filtering of series connection and rectification filtering unit (1) and conversion circuit unit (2); the secondary end of transformer connects output rectification filtering unit (4) and 36V direct current output unit (61); described EMC filtering and rectification filtering unit (1) output also are connected to overload protection and main control circuit unit (3); its output is connected in described conversion circuit unit (2); described overload protection and main control circuit unit (3) are adjusted feedback unit (5) through a photoelectrical coupler to overload detection circuit and load; this overload detection circuit and load are adjusted feedback unit (5) and are connected to described output rectification filtering unit (4); described 36V output unit (61) also is connected in 12V output unit (62), and described 12V direct current output unit (62) also is connected in 3V output unit (63).

2. switching power circuit according to claim 1; it is characterized in that: described overload protection and main control circuit unit (3) are made of TEA1530AT chip (U1) and the peripheral resistance capacitance that connects; its the 8th pin is connected in the output of the filter inductor (LF1) of above-mentioned EMC filtering and rectification filtering unit (1); the 6th pin is connected in the control utmost point of a power switch pipe (Q1), and this power switch pipe (Q1) is serially connected with between the coil and ground of transformer master end.

3. switching power circuit according to claim 1, it is characterized in that: described 12V output unit (62) is to be made of LM2596S-12 chip (U2) and peripheral resistance (R24), electric capacity (E9, E10) and inductance (L3), this resistance (R24) is connected in the Vin end of LM2596S-12 chip (U2), electric capacity (E9) is connected between Vin end and the gnd end, inductance (L3) is connected in the out end output of LM2596S-12 chip (U2), and electric capacity (E10) is connected between inductance (L3) output and the gnd end.

4. switching power circuit according to claim 1, it is characterized in that: described 3V output unit (63) is to be made of LP2985IM5-X3.3 chip (U3) and peripheral electric capacity (C10, E11), this electric capacity (C10) is connected between the bypas end and gnd end of LP2985IM5-X3.3 chip (U3), and this electric capacity (E11) is connected between the out end and gnd end of LP2985IM5-X3.3 chip (U3).