CN217240380U

CN217240380U - Low-cost power supply circuit

Info

Publication number: CN217240380U
Application number: CN202220761280.8U
Authority: CN
Inventors: 王泽伟; 梁荣林; 周波; 刘亚东; 吴光辉
Original assignee: Chongqing Meishun Electronic Technology Co ltd
Current assignee: Chongqing Meishun Electronic Technology Co ltd
Priority date: 2022-04-02
Filing date: 2022-04-02
Publication date: 2022-08-19
Anticipated expiration: 2032-04-02

Abstract

The utility model discloses a low-cost power supply circuit, which comprises a battery, an overcharge and overdischarge voltage detection circuit, a power supply enabling module, a BUCK power supply, an isolation driving circuit, a controller and a charge and discharge current detection circuit; the battery is respectively connected with the overcharge and overdischarge voltage detection circuit, the power supply enabling module and the isolation driving circuit, the power supply enabling module is also respectively connected with the overcharge and overdischarge voltage detection circuit and the BUCK power supply, the BUCK power supply comprises two paths of outputs, one path is connected with the isolation driving circuit, the other path is connected with the controller through an LDO (low dropout regulator), and the controller is also respectively connected with the charge-discharge current detection circuit and the isolation driving circuit; the beneficial effects are as follows: the universal operational amplifier is used as low-cost charge-discharge bidirectional current sampling, so that the cost is reduced, and the universal operational amplifier has price cost advantage for general industrial application and civil use.

Description

Low-cost power supply circuit

Technical Field

The utility model relates to a power management field, concretely relates to low-cost power supply circuit.

Background

At present, due to the shortage of components and parts and chips, the analog front-end chip and the bidirectional current sampling chip of the BMS are high in price, and meanwhile, supply is unstable, so that the market demand is difficult to meet, and the defect that the use cost is too high in the general industrial market and the civil market is overcome. Therefore, a solution that can reduce the cost is needed.

SUMMERY OF THE UTILITY MODEL

To the defect among the prior art, the utility model provides a low-cost power supply circuit for solve the too high defect of cost that adopts simulation front end chip and two-way current sampling chip to bring among the prior art.

The utility model provides a low-cost power supply circuit, which comprises a battery, an overcharge and overdischarge voltage detection circuit, a power supply enabling module, a BUCK power supply, an isolation driving circuit, a controller and a charge and discharge current detection circuit; the battery is respectively connected with the overcharge and overdischarge voltage detection circuit, the power supply enabling module and the isolation driving circuit, the power supply enabling module is further respectively connected with the overcharge and overdischarge voltage detection circuit and the BUCK power supply, the BUCK power supply comprises two paths of outputs, one path is connected with the isolation driving circuit, the other path is connected with the controller through the LDO, and the controller is further respectively connected with the charge-discharge current detection circuit and the isolation driving circuit.

Preferably, the charge and discharge current detection circuit comprises a first operational amplifier, a second operational amplifier, a sampling resistor and a voltage dividing resistor;

one end of the sampling resistor is connected with a system ground, the other end of the sampling resistor is connected with the inverting end of the first operational amplifier through another resistor, the positive end of the first operational amplifier is connected with the divider resistor, the output end of the first operational amplifier is connected with the positive end of the second operational amplifier, the inverting end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is further connected with the controller.

Preferably, a battery enable switch is further connected to the enable end of the power enable module.

Preferably, the BUCK power supply comprises a BUCK controller and an isolation transformer; the BUCK controller outputs two paths of voltage through the isolation transformer, one path of voltage is connected with the isolation driving circuit, and the other path of voltage is connected with the controller through the LDO.

Preferably, the BUCK controller adopts a BUCK direct current converter.

Preferably, the isolation driving circuit comprises an optocoupler, a discharging device Q1 and a charging device Q2;

the trigger end of opto-coupler with the controller is connected, the collecting electrode of opto-coupler pass through a diode with the one end of output all the way is connected in the isolation transformer, the projecting pole of opto-coupler respectively with discharge device Q1's gate and charging device Q2's gate are connected, discharge device Q1's drain electrode with the positive end of battery is connected, discharge device Q1's source with charging device Q2's source electrode is connected, discharge device Q1's source with still between charging device Q2's the source electrode with the other end of output all the way is connected in the isolation transformer, charging device Q2's drain electrode is connected with the positive end of system.

Preferably, the controller employs a microprocessor.

The beneficial effects of the utility model are that:

according to the scheme, an expensive BMS analog front-end chip and an expensive bidirectional current sampling chip are abandoned, and the universal operational amplifier is used for low-cost charge-discharge bidirectional current sampling, so that the cost is reduced, and the scheme has a price cost advantage for general industrial application and civilian use.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

Fig. 1 is a schematic block diagram of a low-cost power circuit according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of a charging/discharging current detection circuit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a circuit structure of a power enable module and a BUCK power supply according to an embodiment of the present invention;

fig. 4 is a schematic circuit diagram of an isolation driving circuit according to an embodiment of the present invention;

fig. 5 is a schematic diagram of an internal structure of a power supply enabling module and an overcharge-overdischarge voltage detection circuit according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

It is to be noted that unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the present invention belongs.

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in the specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

As shown in fig. 1 to 5, an embodiment of the present invention provides a low-cost power circuit, which includes a battery, an overcharge and overdischarge voltage detection circuit, a power enable module, a BUCK power supply, an isolation driving circuit, a controller and a charge and discharge current detection circuit; the battery is respectively connected with the overcharge and overdischarge voltage detection circuit, the power supply enabling module and the isolation driving circuit, the power supply enabling module is further respectively connected with the overcharge and overdischarge voltage detection circuit and the BUCK power supply, the BUCK power supply comprises two paths of outputs, one path of output is connected with the isolation driving circuit, the other path of output is connected with the controller through the LDO, and the controller is further respectively connected with the charge and discharge current detection circuit and the isolation driving circuit.

In implementation, the charge-discharge current detection circuit comprises a first operational amplifier, a second operational amplifier, a sampling resistor and a divider resistor;

It should be noted that, in this embodiment, the sampling resistor is R1 in fig. 2, the other resistor is R3 in fig. 2, the described voltage dividing resistor is R5 in fig. 2, and the controller adopts a Microprocessor (MCU); for more specific connection relations, referring to specific drawings, connection is carried out through pin marks;

two operational amplifiers form a bidirectional current acquisition circuit for acquiring charging current and discharging current. The first op-amp IC4A is an inverse proportional amplifier and the second op-amp IC4B is a follower. The R5 and the R6 divide the voltage and then supply the voltage to the in-phase end (pin 3) of the first operational amplifier as reference voltage, the current sampling signal is transmitted to the anti-phase end (pin 2) of the operational amplifier through the R3, and the R4 is a bias resistor. When the battery is charged, the voltage across the current sampling resistors R1, R2 is positive (for the operational amplifier ground P-), and the voltage across the pin of the first operational amplifier 2 is also positive, which is a large positive value due to the offset resistor R4. When the battery is discharged, the voltage of the current sampling resistors R1 and R2 is negative (for the operational amplifier P-), and the value is added with the positive voltage generated by the bias resistor R4 to become a value which is more than or equal to zero, and then the value is sent to the 2 pins. Thus, the charging current and the discharging current are both converted into positive values and then supplied to the inverting terminal of the operational amplifier.

Furthermore, the enabling end of the power enabling module is also connected with a battery enabling switch, the battery enabling switch is represented by SW1 in the figure, and the power enabling module is connected with the overcharge and overdischarge voltage detection circuit through a CELL-OK pin label;

the internal structure of the overcharge and overdischarge voltage detection circuit adopts a plurality of cascaded S-8209A for detecting the overcharge and overdischarge of the battery; in the drawings, an S-8209A is taken as an example for explanation, and other structures are the same, a first pin of a previous S-8209A is connected with a seventh pin of a next S-8209A, a second pin of the previous S-8209A is connected with a sixth pin of the next S-8209A, and the first pin and the second pin of the last S-8209A are grounded through a resistor respectively.

The internal composition structure of the power supply enabling module comprises Q11, Q12, Q13, Q14 and Q5; the specific connection relationship is shown in the figure, and the principle is as follows:

the cascade S-8209A is used for detection, if one battery is overvoltage, a low level is output corresponding to a CO pin of the S-8209A, so that Q11 is conducted, once Q11 is conducted, Q14 is also conducted, Q13 is also conducted after Q14 is conducted, Q5 is not conducted, subsequent non-conduction is achieved, the LDO and the MCU are not electrified, and cut-off protection is achieved;

similarly, if one of the batteries is under-voltage, the DO pin corresponding to S-8209A outputs low level, so that Q12 is turned on, and once Q12 is turned on, Q14 is also turned on, and Q13 is also turned on after Q14 is turned on, thereby causing Q5 not to be turned on, and the rear stage is not powered.

Meanwhile, in order to further reduce the cost, the BUCK power supply comprises a BUCK controller and an isolation transformer; the BUCK controller outputs two paths of voltage through the isolation transformer, one path of voltage is connected with the isolation driving circuit, and the other path of voltage is connected with the controller through the LDO; the BUCK controller adopts a BUCK direct-current converter, the model number of the BUCK direct-current converter is SCT2A23A, and the BUCK direct-current converter works in a COT mode; the LDO is a linear voltage regulator and comprises LM317 and AZ 1117-3.3;

one path is used for driving an isolation driving circuit to control charging and discharging of a battery (specifically, bias voltage is provided for MOS through D2 rectification); the other path is used for supplying power to the MCU, and the control has the advantages of saving cost and improving reliability.

As can be seen from the figure, the isolation driving circuit comprises an optocoupler, a discharging device Q1 and a charging device Q2;

the trigger end of the optical coupler is connected with the controller, the collector of the optical coupler is connected with one end of one output in the isolation transformer through a diode, the emitter of the optical coupler is respectively connected with the grid of the discharging device Q1 and the grid of the charging device Q2, the drain of the discharging device Q1 is connected with the positive end of the battery, the source of the discharging device Q1 is connected with the source of the charging device Q2, the source of the discharging device Q1 and the source of the charging device Q2 are also connected with the other end of one output in the isolation transformer, and the drain of the charging device Q2 is connected with the positive end of the system; the discharging device Q1 and the charging device Q2 are both MOS tubes.

It should be noted that B + represents the positive terminal of the battery, the system represents the positive terminal of the system output, and the system is controlled by the MOS with or without voltage.

The embodiment of the utility model provides a pair of low-cost power supply circuit has abandoned expensive BMS simulation front end chip and expensive two-way current sampling chip, puts as the two-way current sampling of charge-discharge of low cost with general fortune to the cost is reduced has the price cost advantage to general industrial application and civilian.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the scope of the embodiments of the present invention, and are intended to be covered by the claims and the specification.

Claims

1. A low-cost power supply circuit is characterized by comprising a battery, an overcharge and overdischarge voltage detection circuit, a power supply enabling module, a BUCK power supply, an isolation driving circuit, a controller and a charge and discharge current detection circuit; the battery is respectively connected with the overcharge and overdischarge voltage detection circuit, the power supply enabling module and the isolation driving circuit, the power supply enabling module is further respectively connected with the overcharge and overdischarge voltage detection circuit and the BUCK power supply, the BUCK power supply comprises two paths of outputs, one path is connected with the isolation driving circuit, the other path is connected with the controller through the LDO, and the controller is further respectively connected with the charge-discharge current detection circuit and the isolation driving circuit.

2. The low-cost power supply circuit according to claim 1, wherein the charge and discharge current detection circuit comprises a first operational amplifier, a second operational amplifier, a sampling resistor and a voltage dividing resistor;

3. A low-cost power supply circuit according to claim 2, wherein the enabling terminal of the power supply enabling module is further connected with a battery enabling switch.

4. A low cost power supply circuit as claimed in claim 3, wherein said BUCK power supply includes a BUCK controller and an isolation transformer; the BUCK controller outputs two paths of voltage through the isolation transformer, one path of voltage is connected with the isolation driving circuit, and the other path of voltage is connected with the controller through the LDO.

5. A low cost power supply circuit as claimed in claim 4, wherein said BUCK controller employs a BUCK DC converter.

6. A low-cost power supply circuit according to claim 5, wherein the isolation drive circuit comprises an optocoupler, a discharge device Q1 and a charge device Q2;

7. A low cost power supply circuit as claimed in claim 1, wherein said controller is a microprocessor.