CN215529389U

CN215529389U - EMI isolation dimming power supply

Info

Publication number: CN215529389U
Application number: CN202122170563.3U
Authority: CN
Inventors: 朱金林
Original assignee: Zhongshan Xinchuangming Electronic Technology Co ltd
Current assignee: Guangdong Xinchuang Power Technology Co ltd
Priority date: 2021-09-09
Filing date: 2021-09-09
Publication date: 2022-01-14
Anticipated expiration: 2031-09-09

Abstract

The utility model provides an EMI isolation dimming power supply which is characterized by comprising an EMI circuit, a rectifier bridge, a voltage stabilization protection circuit, a switching circuit and a filtering output circuit which are sequentially connected, wherein the switching circuit comprises a single chip microcomputer U1, a driving chip U2, a switching tube Q1 and a transformer, one end of a primary winding L1 of the transformer is connected with a high-voltage end of the rectifier bridge, and the other end of the primary winding L1 of the transformer is grounded through the switching tube Q1; the first secondary winding L2 of the transformer is connected with a filter output circuit; the driving chip U2 is controlled by a single chip microcomputer U1, which has a driving end connected with the gate of the switching tube Q1, and the single chip microcomputer has a dimming signal input end for obtaining a dimming signal. The flyback DC-DC conversion circuit meets the driving requirement of the load, provides better electrical isolation for an internal chip, and sets an EMI circuit and a voltage stabilization protection circuit in consideration of resisting severe power grid environment, so that the anti-surge level is improved, and the safety of the internal circuit of the power supply and subsequent loads is protected.

Description

EMI isolation dimming power supply

Technical Field

The utility model relates to an EMI isolation dimming power supply applied to a street lamp.

Background

Mainstream street lamp driving power supply's function is single relatively in the market, can't adjust luminance according to the demand, and the operational environment that the street lamp faced is abominable moreover, faces the surge impact in the electric wire netting often, consequently, realizes that street lamp intellectuality's control chip has higher to the inside isolation of power and security requirement.

SUMMERY OF THE UTILITY MODEL

The utility model provides an EMI isolation dimming power supply, which is realized by the following technical means: the power supply comprises an EMI circuit, a rectifier bridge, a voltage stabilization protection circuit, a switching circuit and a filtering output circuit which are connected in sequence, wherein the switching circuit comprises a single chip microcomputer U1, a driving chip U2, a switching tube Q1 and a transformer, one end of a primary winding L1 of the transformer is connected with the high-voltage end of the rectifier bridge, and the other end of the primary winding L1 of the transformer is grounded through the switching tube Q1; the first secondary winding L2 of the transformer is connected with a filter output circuit; the driving chip U2 is controlled by a single chip microcomputer U1, which has a driving end connected with the gate of the switching tube Q1, and the single chip microcomputer has a dimming signal input end for obtaining a dimming signal.

In one or more embodiments of the present invention, one end of the second secondary winding L3 of the transformer is grounded, and the other end is connected to the power supply terminal of the driving chip U2 through the diode D2 and the current limiting resistor R3.

In one or more embodiments of the present invention, the filter output circuit includes a diode D1, a resistor R10, a capacitor C2 and a capacitor C10, an anode of the diode D1 is connected to the high potential end of the first secondary winding L2, and the capacitor C2 is connected between a cathode of the diode D1 and the low potential end of the first secondary winding L2, and both ends of the capacitor are used as the output end of the filter output circuit; the resistor R10 is connected in series with the capacitor C10 and then connected in parallel with the diode D1.

In one or more embodiments of the present invention, the control terminal of the single chip U1 is connected to the dimming terminal of the driving chip U2 through a voltage divider circuit, the voltage divider circuit includes voltage dividing resistors R8 and R5, and a capacitor C5 is connected in parallel to two terminals of the resistor R5.

In one or more embodiments of the present invention, the EMI circuit includes a common mode choke L1, filter capacitors C11, C12, C13, and C14, and a series mode choke L2; the two input ends of the common mode choke coil L1 are connected in parallel with a filter capacitor C11, and the two output ends are respectively butted with the two input ends of the series mode choke coil L2; the filter capacitor C12 is connected in parallel between the two output terminals of the series-mode choke coil L2, the filter capacitors C12 and C13 are connected in series between the two input terminals of the series-mode choke coil L2, and the connection point of the filter capacitors C12 and C13 is grounded.

In one or more embodiments of the present invention, the input end of the common mode choke coil L1 is further provided with a fuse F1 and a voltage dependent resistor RV 1.

In one or more embodiments of the present invention, the output terminal of the rectifier bridge is connected to the voltage regulator ZD 1.

In one or more embodiments of the present invention, the dimming signal input terminal of the single-chip microcomputer U1 is connected to a potentiometer signal, a 0-10V level signal or a PWM signal through a terminal J1.

In one or more embodiments of the present invention, the single chip microcomputer U1 is connected to a temperature sensing circuit, the temperature sensing circuit includes a temperature probe and an optical coupling isolation module U3, an input end of the optical coupling isolation module U3 is connected to the temperature probe, an output end thereof is connected to the single chip microcomputer U1, and the output end is connected to a resistor R15 and a capacitor C15 in parallel.

In one or more embodiments of the present invention, the single chip microcomputer U1 is connected to or integrated with a wireless communication module for communicating with a host system.

The utility model has the beneficial effects that: the flyback DC-DC conversion circuit is adopted to meet the driving requirement of the load, good electrical isolation is provided for the single chip microcomputer U1, the driving chip U2 and the like, meanwhile, in consideration of resistance to severe power grid environment, the power supply is provided with the EMI circuit and the voltage stabilization protection circuit on the front side and the rear side of the rectifier bridge, the anti-surge level is improved, the safety of the internal circuit of the power supply and subsequent loads is protected, and good insulation performance and safety are achieved.

Drawings

Fig. 1 is a circuit architecture diagram of the present invention.

Fig. 2 is a schematic circuit diagram of the present invention.

Detailed Description

The application is further described below with reference to the accompanying drawings:

referring to fig. 1 to 2, the EMI isolation dimming power supply includes an EMI circuit, a rectifier bridge, a voltage stabilization protection circuit, a switching circuit, and a filter output circuit, which are connected in sequence, the switching circuit includes a single chip microcomputer U1, a driving chip U2, a switching tube Q1, and a transformer, one end of a primary winding L1 of the transformer is connected to a high-voltage end of the rectifier bridge, and the other end is grounded through the switching tube Q1; the first secondary winding L2 of the transformer is connected with a filter output circuit; the driving chip U2 is controlled by a single chip microcomputer U1, which has a driving end connected with the gate of the switching tube Q1, the single chip microcomputer has a dimming signal input end for obtaining a dimming signal, one end of a second secondary winding L3 of the transformer is grounded, and the other end is connected with the power supply end of the driving chip U2 through a diode D2 and a current limiting resistor R3. The dimming signal input end of the singlechip U1 is connected with a potentiometer signal, a 0-10V level signal or a PWM signal through a terminal J1, and the singlechip U1 generates a driving signal for the driving chip U1 according to the signals. The filter output circuit comprises a diode D1, a resistor R10, a capacitor C2 and a capacitor C10, wherein the anode of the diode D1 is connected with the high potential end of the first secondary winding L2, the capacitor C2 is connected between the cathode of the diode D1 and the low potential end of the first secondary winding L2, and two ends of the capacitor C2 are used as the output end of the filter output circuit; the resistor R10 is connected in series with the capacitor C10 and then connected in parallel with the diode D1. The control end of the singlechip U1 is connected with the dimming end of the driving chip U2 through a voltage division circuit, the voltage division circuit comprises voltage division resistors R8 and R5, and two ends of the resistor R5 are connected with a capacitor C5 in parallel.

When the power supply is just started, the output voltage of the switch circuit is not stable, and the driving chip U2 passes through the resistor R_VCCWhen the output circuit of the switch circuit is stabilized, the stabilized voltage is coupled through a second secondary winding L3 of the transformer and is provided for a driving chip U2 through a diode D2 and a current-limiting resistor R3; the model of the driving chip U2 is ZCC7331, the driving signal of the single chip microcomputer U1 is obtained through a DIM pin, then a PWM signal is sent to the grid electrode of the switching tube Q1 through the GATE end of the driving chip U2, the on-off of the switching tube Q1 is controlled, then the primary winding L1 of the transformer is matched to realize the electric output conversion of the high-voltage end of the rectifier bridge BD1, the diode D1 is used for preventing voltage reverse bias, and the capacitors C2 and C10 are used for output voltage filtering. Output of rectifier bridge BD1The input side and the output side are respectively provided with an EMI circuit and a voltage stabilization protection circuit, so that the surge condition in a power grid can be dealt with.

Specifically, the EMI circuit includes a common mode choke L1, filter capacitors C11, C12, C13, and C14, and a series mode choke L2; the two input ends of the common mode choke coil L1 are connected in parallel with a filter capacitor C11, and the two output ends are respectively butted with the two input ends of the series mode choke coil L2; the filter capacitor C12 is connected in parallel between two output ends of the series mode choke coil L2, the filter capacitors C12 and C13 are connected in series and then connected between two input ends of the series mode choke coil L2, a connection point of the filter capacitors C12 and C13 is grounded, the input end of the common mode choke coil L1 is further provided with a protective tube F1 and a piezoresistor RV1, and the voltage stabilization protection circuit comprises a voltage stabilization tube ZD1 arranged at an output end of a rectifier bridge. The common mode choke coil L1 is used for dealing with common mode interference, and the two coils have the same magnetic flux direction, and the total inductance is increased rapidly through coupling, so that the common mode choke coil has larger impedance to common mode signals. Capacitors C13 and C14 are connected across the output end of the common mode choke L1, and the midpoint is grounded, so that the common mode signal can be effectively suppressed, the capacitor should not exceed 0.1F to reduce the leakage current, and the series mode choke L2 is used to cope with the series mode interference. Capacitors C11 and C12, respectively disposed at the front and rear ends of the EMI circuit, may be thin film capacitors, which contribute to the elimination of common mode signals.

In consideration of the working over-temperature condition, the single chip microcomputer U1 is connected with a temperature sensing circuit, the temperature sensing circuit comprises a temperature probe and an optical coupling isolation module U3, the input end of the optical coupling isolation module U3 is connected with the temperature probe, the output end of the optical coupling isolation module U3 is connected with the single chip microcomputer U1, and the output end of the optical coupling isolation module U3 is connected with a resistor R15 and a capacitor C15 in parallel; the temperature probe is arranged at a light source load to obtain real-time temperature, when the temperature exceeds the limit, the single chip microcomputer U1 forcibly reduces the brightness of the output light source load to buffer and cool down, the wireless communication module is connected with or integrated with the temperature probe to communicate with an upper system for alarming, and corresponding control instructions, such as synchronous instructions, brightness adjustment instructions, switch instructions and the like, can be obtained through the wireless communication module to realize the networking control of the street lamp.

The above preferred embodiments should be considered as examples of the embodiments of the present application, and technical deductions, substitutions, improvements and the like similar to, similar to or based on the embodiments of the present application should be considered as the protection scope of the present patent.

Claims

1. An EMI isolation dimming power supply is characterized by comprising an EMI circuit, a rectifier bridge, a voltage stabilization protection circuit, a switch circuit and a filtering output circuit which are sequentially connected, wherein the switch circuit comprises a single chip microcomputer U1, a driving chip U2, a switch tube Q1 and a transformer, one end of a primary winding L1 of the transformer is connected with a high-voltage end of the rectifier bridge, and the other end of the primary winding L1 of the transformer is grounded through the switch tube Q1; the first secondary winding L2 of the transformer is connected with a filter output circuit; the driving chip U2 is controlled by a single chip microcomputer U1, which has a driving end connected with the gate of the switching tube Q1, and the single chip microcomputer has a dimming signal input end for obtaining a dimming signal.

2. The EMI isolated dimming power supply of claim 1, wherein one end of the second secondary winding L3 of the transformer is grounded, and the other end is connected to the power supply terminal of the driver chip U2 via the diode D2 and the current limiting resistor R3.

3. The EMI isolated dimming power supply of claim 1, wherein the filtering output circuit comprises a diode D1, a resistor R10, a capacitor C2 and a capacitor C10, wherein the anode of the diode D1 is connected to the high potential end of the first secondary winding L2, the capacitor C2 is connected between the cathode of the diode D1 and the low potential end of the first secondary winding L2, and both ends of the capacitor are used as the output end of the filtering output circuit; the resistor R10 is connected in series with the capacitor C10 and then connected in parallel with the diode D1.

4. The EMI isolation dimming power supply of claim 1, wherein the control terminal of the single chip U1 is connected to the dimming terminal of the driver chip U2 via a voltage divider circuit, the voltage divider circuit comprises voltage divider resistors R8 and R5, and a capacitor C5 is connected in parallel to two terminals of the resistor R5.

5. The EMI isolated dimming power supply of any one of claims 1-4, wherein the EMI circuit comprises common mode choke L1, filter capacitors C11, C12, C13 and C14, and series mode choke L2; the two input ends of the common mode choke coil L1 are connected in parallel with a filter capacitor C11, and the two output ends are respectively butted with the two input ends of the series mode choke coil L2; the filter capacitor C12 is connected in parallel between the two output terminals of the series-mode choke coil L2, the filter capacitors C12 and C13 are connected in series between the two input terminals of the series-mode choke coil L2, and the connection point of the filter capacitors C12 and C13 is grounded.

6. The EMI isolated dimming power supply of claim 5, wherein the input terminal of the common mode choke L1 is further provided with a fuse F1 and a voltage dependent resistor RV 1.

7. The EMI isolated dimming power supply of any one of claims 1-4, wherein the output terminal of the rectifier bridge is connected with a voltage regulator ZD 1.

8. The EMI isolated dimming power supply of any one of claims 1-4, wherein the dimming signal input of the single-chip U1 is connected to a potentiometer signal, a 0-10V level signal or a PWM signal through a terminal J1.

9. The EMI isolation dimming power supply according to any one of claims 1-4, wherein the single chip microcomputer U1 is connected with a temperature sensing circuit, the temperature sensing circuit comprises a temperature probe and an optical coupling isolation module U3, the input end of the optical coupling isolation module U3 is connected with the temperature probe, the output end of the optical coupling isolation module U3 is connected with the single chip microcomputer U1, and the output end of the optical coupling isolation module U3 is connected with a resistor R15 and a capacitor C15 in parallel.

10. The EMI isolated dimming power supply of any one of claims 1-4, wherein the single chip microcomputer U1 is connected with or integrated with a wireless communication module for communicating with an upper system.