CN115912899B

CN115912899B - Capacitor series voltage dividing circuit

Info

Publication number: CN115912899B
Application number: CN202310133668.2A
Authority: CN
Inventors: 胡三义
Original assignee: Guangdong Dongling Power Technology Co ltd
Current assignee: Guangdong Dongling Power Technology Co ltd
Priority date: 2023-02-20
Filing date: 2023-02-20
Publication date: 2023-05-23
Anticipated expiration: 2043-02-20
Also published as: CN115912899A

Abstract

A capacitor series voltage dividing circuit comprises a relay K1, wherein a voltage is input to a coil end of the relay K1, a voltage V < 0+ > is input to one end of a conducting end of the relay K1, the other end of the conducting end is connected with an input end VBUS, the input end VBUS is connected with an electrolytic capacitor EC1 and an electrolytic capacitor EC2 which are sequentially connected in series, one end of the electrolytic capacitor EC2 is grounded, an endpoint V1 is commonly connected between a negative electrode of the electrolytic capacitor EC1 and a positive electrode of the electrolytic capacitor EC2, and the endpoint V1 is grounded through a resistor R4, a resistor R5 and a resistor R6 which are sequentially connected in series; the voltage V0+ is further connected with the resistor R4 through the resistor R1, the resistor R2 and the resistor R3 which are sequentially connected in series, the voltage dividing resistor is connected to the 2 pin of the K1 relay, the voltage is equally divided at the V1 end point through the K1 pull-in resistor in normal operation, and the voltage is not divided at the V1 end point through the K1 break resistor in standby state.

Description

Capacitor series voltage dividing circuit

Technical Field

The invention relates to the field of LED power supplies, in particular to a capacitive series voltage dividing circuit.

Background

In recent years, the LED power supply is gradually developed from current middle and small power to middle and large power. The power of the plant lamp in the important field of the LED power supply is also developed from the level of hundred watts to the direction of kilowatts or even more, and because the current specification of the input range of the LED power supply is mostly 120-277V of alternating current, the line loss of the power grid in the input voltage range is up to about 25% of the total electric energy of the related branch according to statistics of related departments. Especially, the line loss of the ultra-high power supply grid is more serious. Thus high input voltage power supplies have evolved. By adopting the working mode of inputting 380V (380V of two live wires in North America and the inner land), the line loss of the power grid can be greatly reduced, and the cost of construction cables can be reduced. For the power supply, the input voltage is high, the input current is greatly reduced, and the material cost of the input stage and the PFC module part can be greatly reduced. However, a high input voltage range (AC 240V-528V) occurs, and PFC is raised to >528V 1.414=750v in order to meet power factor and harmonic requirements. Such high PFC voltages result in the energy storage electrolytic capacitor requiring at least two serially operated capacitors. However, the capacitance of the electrolytic capacitor has an error of +/-20%, if the capacitance of one capacitor is +20% and the capacitance of the other capacitor is-20%, the two capacitors connected in series are seriously and unevenly divided, so that one capacitor bears a voltage far exceeding the self-bearing voltage, and the capacitor is quickly failed, so that the power supply is damaged and cannot work. If two 450V electrolytic capacitors with higher withstand voltage are selected to be connected in series, the volume is larger, the price is high, the capacity is relatively smaller, the use requirement cannot be met, the problem that one capacitor bears higher voltage is still not changed although the serious unbalance phenomenon of voltage equalizing can be improved, in order to keep the same voltage dividing effect of the two capacitors connected in series, the capacitors are equally divided by resistors, the voltage dividing effect cannot be achieved due to the fact that the current flowing through the resistors is smaller due to the fact that the resistance is too large, the good voltage equalizing effect can be achieved due to the fact that the resistance is relatively smaller, and standby power consumption can be seriously affected.

Disclosure of Invention

In order to solve the above problems, the present technical solution provides a capacitive series voltage dividing circuit.

In order to achieve the above purpose, the technical scheme is as follows:

a capacitive series voltage divider circuit comprising;

the relay K1 is characterized in that a voltage is input to a coil end of the relay K1, a voltage V < 0+ > is input to one end of a conducting end of the relay K1, the other end of the conducting end is connected with an input end VBUS, the input end VBUS is connected with an electrolytic capacitor EC1 and an electrolytic capacitor EC2 which are sequentially connected in series, one end of the electrolytic capacitor EC2 is grounded, an endpoint V1 is commonly connected between a negative electrode of the electrolytic capacitor EC1 and a positive electrode of the electrolytic capacitor EC2, and the endpoint V1 is grounded through a resistor R4, a resistor R5 and a resistor R6 which are sequentially connected in series;

the voltage V < 0+ > is also connected with the resistor R4 through a resistor R1, a resistor R2 and a resistor R3 which are sequentially connected in series.

In some embodiments, the resistances of the resistors R1, R2, R3, R4, R5, and R6 are 200K.

In some embodiments, the voltage values of the electrolytic capacitor EC1 and the electrolytic capacitor EC2 are 400V.

The beneficial effects of the application are that:

the voltage dividing resistor is connected to the 2 pins of the K1 relay, the voltage of the K1 pull-in resistor is equally divided at the end point of V1 during normal operation, and the voltage of the K1 break resistor is not divided at the end point of V1 during standby state. Thereby achieving the effects of voltage division without influencing standby power consumption. Not only solves the unbalance problem, but also solves the problem of influencing the standby power consumption.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the description of the embodiments will be briefly described below.

Fig. 1 is a schematic structural view of an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects solved by the invention more clear, the 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 for purposes of illustration only and are not intended to limit the scope of the invention.

Referring to fig. 1, a capacitive series voltage divider circuit includes; the relay K1 is characterized in that a voltage is input to a coil end of the relay K1, a voltage V < 0+ > is input to one end of a conducting end of the relay K1, the other end of the conducting end is connected with an input end VBUS, the input end VBUS is connected with an electrolytic capacitor EC1 and an electrolytic capacitor EC2 which are sequentially connected in series, one end of the electrolytic capacitor EC2 is grounded, an endpoint V1 is commonly connected between a negative electrode of the electrolytic capacitor EC1 and a positive electrode of the electrolytic capacitor EC2, and the endpoint V1 is grounded through a resistor R4, a resistor R5 and a resistor R6 which are sequentially connected in series; the voltage V < 0+ > is further connected with the resistor R4 through a resistor R1, a resistor R2 and a resistor R3 which are sequentially connected in series, the resistance values of the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R5 and the resistor R6 are 200K, and the voltage values of the electrolytic capacitor EC1 and the electrolytic capacitor EC2 are 400V.

In specific implementation, the VBUS input terminal is PFC voltage, the VBUS input terminal is connected to pin 1 of the electrolytic capacitor EC1, pin 2 of the electrolytic capacitor EC1 is connected to pin 1 of the electrolytic capacitor EC2, where the terminal V1 is formed, and pin 2 of the electrolytic capacitor EC2 is connected to GND. The input end of VBUS is connected to 1 pin of relay K1, 2 pin of K1 is connected to 1 pin of resistance R1, form terminal VO+, 2 pin of resistance R1 is connected to 1 pin of resistance R2, 2 pin of resistance R2 is connected to one pin of resistance R3, 2 pin of resistance R3 is connected to V1 terminal, V1 terminal is connected to 1 pin of resistance R4, 2 pin of resistance R4 is connected to 1 pin of resistance R5, 2 pin of resistance R5 is connected to 1 pin of resistance R6, 2 pin of resistance R6 is connected to GND, VS is a relay control signal, VS is connected to 5 pins of K1 of relay, 6 pins of K1 are connected to VSS, when the product is started and normally works, VS outputs high level 12V to be added to P5 pins of contacts of a relay K1, relay is sucked, PFC starts to work, and BUS voltage rises to 750V for work of a subsequent circuit. The 6 200K 1206 resistors divide the voltage of the two electrolytic capacitors connected in series through the pin P2 of the K1 contact, so that the same voltage born by each capacitor is achieved, when the product enters a standby working state, the VS output low-level relay K1 is disconnected, PFC stops working, the BUS voltage is reduced to 540V (AC 380V 1.414), the 6 series resistors stop dividing the voltage, and even if the voltage of the two capacitors is unequal due to capacity errors, the rated bearing voltage of 400V of each capacitor is not reached, and the voltage of the capacitor is stopped due to the disconnection of the voltage dividing resistor, so that the power consumption of the machine is not influenced.

Working principle: when the power-on is started, VS outputs a 12V signal to a pin 5 of a coil contact of the relay K1, K1 is attracted, PFC starts to work, the BUS voltage is increased to 750V, the BUS voltage is connected to a pin 1 of the resistor R1 through a pin 1 and a pin 2 of the relay K1, the BUS voltage is divided by the R1, R2, R3 pair R4, R5, R6 resistor in series, the accurate voltage division at the V1 end point is 750V/2=375V, and the 375V is smaller than the rated voltage 400V of the capacitor, so that the capacitor can work normally for a long time.

When the power-off or standby working state is entered, a low-level 0V signal output by VS is connected to a pin 5 of a coil contact of K1, K1 is disconnected, PFC stops working, the voltage of BUS drops to about 540V DC (AC 380V 1.414=537V DC), a pin 1 and a pin 2 of K1 are disconnected, and R1, R2 and R3 are in voltage division for R4, R5 and R6, so that the resistance loss is negligible, and the standby power consumption is not influenced. Because the BUS voltage drops to about 540V, even if the voltage division of the two capacitors is unequal due to the +/-20% of capacity error, the voltage born by each capacitor is far lower than the rated value 400V, so that the capacitor and the product are not influenced, and the working process is repeated.

In some embodiments, the resistance of R1, R2, R3, R4, R5, R6 is 200K, which can have good voltage division and low resistance power consumption.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the scope of the present application, but other principles and basic structures are the same or similar to the present application.

Claims

1. A capacitive series voltage divider circuit, comprising;

the voltage V < 0+ > is also connected with the resistor R4 through a resistor R1, a resistor R2 and a resistor R3 which are sequentially connected in series;

the power supply circuit is characterized by further comprising an input end VBUS from PFC, wherein the input end VBUS is connected with an electrolytic capacitor EC1, an endpoint V1 is formed between the electrolytic capacitor EC1 and the electrolytic capacitor EC2, one end of the electrolytic capacitor EC2 is connected with GND, the input end VBUS is connected to one end of a switch end of a relay K1, the other end of the switch end of the relay K1 is connected with an input voltage V0 < + >, a resistor R1 is connected with the endpoint V1 through a resistor R2 and a resistor R3, when a product is started and normally works, a relay control signal VS outputs a high level on the relay K1, the relay K1 is sucked in, PFC starts to work, the voltage of the input end VBUS is increased to 750V for a later-stage circuit to work, and the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R5 and the resistor R6 are divided by the relay K1 and the electrolytic capacitor EC2, so that the same voltage is born by the electrolytic capacitor EC1 and the resistor C2, when the product enters a standby working state, the relay control signal output low level PFC stops, the relay VBUS stops working, and the resistor R1 stops working, and the resistor R4, the resistor R4 and the resistor R5 stops the voltage dividing circuit from working because the voltage of the resistor R1, the resistor R4 and the resistor R4 is stopped.

2. A capacitive series divider circuit according to claim 1, characterized in that: the resistance values of the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R5 and the resistor R6 are 200K.

3. A capacitive series divider circuit according to claim 2, characterized in that: the voltage values of the electrolytic capacitor EC1 and the electrolytic capacitor EC2 are 400V.