CN218526127U

CN218526127U - Constant voltage and constant current circuit realized by utilizing switching technology

Info

Publication number: CN218526127U
Application number: CN202122223819.2U
Authority: CN
Inventors: 王定国; 余定益; 李嘉龙
Original assignee: Dongguan Sunstrong Electric Machinery Co ltd
Current assignee: Dongguan Sunstrong Electric Machinery Co ltd
Priority date: 2021-09-14
Filing date: 2021-09-14
Publication date: 2023-02-24
Anticipated expiration: 2031-09-14

Abstract

The utility model discloses an utilize switching technique to realize constant voltage and constant current circuit, it includes: the transformer module is connected with a forward excitation module and a flyback module, the DC output module is connected with a constant voltage and constant current switching module, and the flyback module and the constant voltage and constant current switching module are connected with a main control chip module. Through adopting main control chip module real time monitoring charging voltage, when charging voltage reaches first settlement voltage, this charging current can reduce a step to realize independent constant voltage function through constant voltage constant current switching module, with constant voltage and constant current function, utilize constant voltage circuit can give outside V output voltage, outside output voltage can bear certain peak current.

Description

Constant voltage and constant current circuit realized by utilizing switching technology

The technical field is as follows:

the utility model relates to a technical field that charges refers in particular to an utilize switching technique to realize constant voltage and constant current circuit.

The background art comprises the following steps:

at present, battery chargers are all charged at constant current and constant voltage, one side of a secondary circuit is formed by adding two operational amplifiers and a reference voltage or a control feedback IC (integrated circuit) AP4310 which is formed into the constant current and the constant voltage, the charging is not carried out by segmented current, the battery is not fully charged, because the voltage difference exists in the battery during large-current charging, the internal parameters of the battery include impedance and the charging current RxI = V, when R =0.05 ohm and the charging current I =10A is charged, the battery voltage is 0.5V higher, the full charging voltage of 5 lithium batteries is 21V, a monitoring circuit (U71 and the periphery) detects that the charging is stopped at 21V, and the actual voltage of the battery is only 20.5V, so that the battery is not fully charged.

In view of the above, the present inventors propose the following.

The utility model has the following contents:

an object of the utility model is to overcome prior art's is not enough, provide one kind and utilize the switching technology to realize constant voltage and constant current circuit.

In order to solve the technical problem, the utility model discloses a following technical scheme: this utilize switching technique to realize constant voltage and constant current circuit includes: the transformer module is connected with a forward excitation module and a flyback module, the DC output module is connected with a constant voltage and constant current switching module, and the flyback module and the constant voltage and constant current switching module are connected with a main control chip module.

Further, in the above technical solution, the constant voltage and constant current switching module includes a constant current unit, a constant voltage and constant current switching unit connected to the constant current unit, and a constant voltage unit connected to the constant voltage and constant current switching unit, the constant voltage unit and the constant current unit are respectively connected to an anode and a cathode of the DC output module, the constant current unit is further connected to the flyback module and the main control chip module, and the constant voltage and constant current switching unit is further connected to the flyback module and the main control chip module.

Further, in the above technical solution, the constant voltage unit and the constant current unit are connected to the forward module through an optocoupler U2 and an optocoupler U4, respectively.

Further, in the above technical solution, the constant voltage and constant current switching unit includes a resistor R50 connected to the optocoupler U4, a MOS transistor Q192 connected to the resistor R50, a MOS transistor Q129 and a resistor R49 connected to the MOS transistor Q192, and a resistor R47 and a resistor R48 connected to the MOS transistor Q129, where the resistor R47 is connected to a CC SW pin of the main control chip module, the resistor R49 and the MOS transistor Q192 are connected to a +12V terminal of the flyback module, and the MOS transistor Q129 and the resistor R48 are further connected to an SGND ground terminal.

Further, in the above technical solution, the constant voltage unit includes a resistor R41 and a resistor R43 connected to the positive electrode of the DC output module, a resistor R44 and a resistor R45 and a resistor R46 connected to the resistor R43, a capacitor C45 connected to the resistor R46, an optocoupler U2 connected to the resistor R41 and the capacitor C45, a voltage regulator U115 connected to the optocoupler U2 and the resistor R43, and a resistor R42 connected in parallel to the optocoupler U2, where the voltage regulator U115, the resistor R44, and the resistor R45 are further connected to an SGND ground terminal.

Further, in the above technical solution, the constant current unit includes a single-channel operational amplifier U100A, a resistor R52 and a resistor R51 connected to pins 3 in the single-channel operational amplifier U100A, a capacitor C113 connected to pins 4 in the single-channel operational amplifier U100A and the resistor R51, a resistor R55A, and a capacitor C42 connected to pins 1 in the single-channel operational amplifier U100A, pins 4 of the single-channel operational amplifier U100A are further connected to the optocoupler U4, a negative electrode in the single-channel operational amplifier U100A, the resistor R55, and the capacitor C42 are further connected to an SGND ground terminal, the resistor R55A is connected to a pin CC PWM of the main control chip module, and a positive electrode in the single-channel operational amplifier U100A is connected to a +12V end of the flyback module.

Further, in the above technical solution, the pin 1 in the single-channel operational amplifier U100A is connected to the pin +2.5V of the main control chip module through a resistor R54, and is connected to the pin +5V of the main control chip module through a resistor 53.

Further, in the above technical solution, an MOS transistor Q61 is arranged in the flyback module, the MOS transistor Q61 is connected to the forward module through an optocoupler PC3, and the MOS transistor Q61 is further connected to a Charging on pin of the main control chip module through a resistor R65; and the optocoupler PC3 is switched on through an MOS (metal oxide semiconductor) tube Q2 to provide the working voltage of the chip U1 in the forward module.

Further, in the above technical solution, a voltage monitoring module is further connected to the positive electrode of the DC output module.

Further, in the above technical solution, a moded pin of the main control chip module is connected with a SW-1 switch module for switching between a constant voltage charging mode and a constant current charging mode.

After the technical scheme is adopted, compared with the prior art, the utility model has following beneficial effect: the utility model discloses in through adopting main control chip module real time monitoring charging voltage, reach first settlement voltage when charging voltage, this charging current can reduce a step to realize independent constant voltage function through constant voltage constant current switching module, with constant voltage and constant current function, utilize constant voltage circuit can give outside V output voltage, outside output voltage can bear certain peak current.

Description of the drawings:

fig. 1 is a circuit diagram of the present invention;

fig. 2 is a circuit diagram of the constant voltage and constant current switching module of the present invention;

fig. 3 is a circuit diagram of a flyback module according to the present invention;

fig. 4 is a circuit diagram of a forward module according to the present invention;

fig. 5 is a circuit diagram of the main control chip module of the present invention;

FIG. 6 is a circuit diagram of a SW-1 switch module of the present invention;

fig. 7 is a circuit diagram of the medium voltage monitoring module of the present invention.

The specific implementation mode is as follows:

the present invention will be further described with reference to the following specific embodiments and the accompanying drawings.

Referring to fig. 1 to 7, a circuit for implementing a constant voltage and a constant current by using a switching technique includes: the transformer type electromagnetic interference power supply comprises an AC input module 1, an EMI filtering module 2, an input rectifying and filtering module 3, a transformer module 4, an output rectifying and filtering module 5 and a DC output module 6 which are sequentially connected, wherein the transformer module 4 is connected with a forward module 7 and a flyback module 8, the DC output module 6 is connected with a constant voltage and constant current switching module 9, and the flyback module 8 and the constant voltage and constant current switching module 9 are connected with a main control chip module 10. Through adopting main control chip module 10 real time monitoring charging voltage, when charging voltage reaches first settlement voltage, this charging current can reduce a step to realize independent constant voltage function through constant voltage constant current switch module 9, with constant voltage and constant current function, utilize constant voltage circuit can give outside 24V output voltage, outside output voltage can bear certain peak current. For example, in the place of motor, the motor is started or operates under heavy load, the rated current is exceeded instantly, and if the constant voltage and constant current circuit is used, the output voltage is directly pulled off as long as the output current exceeds the constant current.

The constant voltage and constant current switching module 9 includes a constant current unit 91, a constant voltage and constant current switching unit 92 connected to the constant current unit 91, and a constant voltage unit 93 connected to the constant voltage and constant current switching unit 92, the constant voltage unit 93 and the constant current unit 91 are respectively connected to the positive electrode and the negative electrode of the DC output module 6, the constant current unit 91 is further connected to the flyback module 8 and the main control chip module 10, and the constant voltage and constant current switching unit 92 is further connected to the flyback module 8 and the main control chip module 10.

The constant voltage unit 93 and the constant current unit 91 are respectively connected with the forward module 7 through an optical coupler U2 and an optical coupler U4.

The constant voltage and constant current switching unit 92 comprises a resistor R50 connected with the optocoupler U4, a MOS transistor Q192 connected with the resistor R50, a MOS transistor Q129 and a resistor R49 connected with the MOS transistor Q192, and a resistor R47 and a resistor R48 connected with the MOS transistor Q129, wherein the resistor R47 is connected with a CC SW pin of the main control chip module 10, the resistor R49 and the MOS transistor Q192 are connected with a +12V end of the flyback module 8, and the MOS transistor Q129 and the resistor R48 are further connected with an SGND ground terminal.

The constant voltage unit 93 includes a resistor R41 and a resistor R43 connected to the positive electrode of the DC output module 6, a resistor R44 and a resistor R45 and a resistor R46 connected to the resistor R43, a capacitor C45 connected to the resistor R46, an optocoupler U2 connecting the resistor R41 and the capacitor C45, a voltage regulator U115 connecting the optocoupler U2 and the resistor R43, and a resistor R42 connected in parallel to the optocoupler U2, wherein the voltage regulator U115, the resistor R44, and the resistor R45 are further connected to an SGND ground terminal.

The constant current unit 91 includes a single-path operational amplifier U100A, a resistor R52 and a resistor R51 connected to pins 3 of the single-path operational amplifier U100A, a capacitor C113 connected to pins 4 of the single-path operational amplifier U100A and the resistor R51, a resistor R55A, and a capacitor C42 connected to pins 1 of the single-path operational amplifier U100A, pins 4 of the single-path operational amplifier U100A are further connected to the optocoupler U4, a negative electrode of the single-path operational amplifier U100A, the resistor R55, and the capacitor C42 are further connected to an SGND ground terminal, the resistor R55A is connected to a CC PWM pin of the main control chip module 10, and a positive electrode of the single-path operational amplifier U100A is connected to a +12V terminal of the flyback module 8.

The pin 1 in the single-path operational amplifier U100A is connected to the pin +2.5V of the main control chip module 10 through a resistor R54, and is connected to the pin +5V of the main control chip module 10 through a resistor 53.

An MOS tube Q61 is arranged in the flyback module 8, the MOS tube Q61 is connected with the forward module 7 through an optocoupler PC3, and the MOS tube Q61 is also connected with a Charging on pin of the main control chip module 10 through a resistor R65; and the optocoupler PC3 is switched on through an MOS (metal oxide semiconductor) tube Q2 to provide the working voltage of the chip U1 in the forward module 7.

The positive pole of the DC output module 6 is also connected to a voltage monitoring module 61.

The MODDE pin of the main control chip module 10 is connected with a SW-1 switch module 101 for switching between a constant voltage charging mode and a constant current charging mode.

In this embodiment, the charging voltage is detected by the secondary improved circuit and the MCU circuit, so as to realize the following intelligent charging curve

1. A constant current stage:

as the name suggests, constant current charging is adopted, so that the phenomenon that too low electric quantity leads to excessive current charging, and therefore, the battery generates heat, fires and irreparable damage are avoided. The charging mechanism is as follows: the charging current of the charger is kept constant, the charging quantity is stably increased, and the voltage of the battery gradually rises;

2 constant pressure stage:

as the name implies, constant voltage charging is used to ensure that the battery eventually reaches the rated voltage.

The charging mechanism is as follows: the charging voltage is kept constant, and the battery voltage slowly rises until the rated voltage of the battery is reached;

3, floating and charging stage:

as the name suggests, it is satisfied that the charging current is very small when entering the dragonfly water-lighting stage, which is the key stage of battery maintenance.

The charging mechanism is as follows: the storage battery is fully charged, the charging voltage and the battery voltage are basically equal, the charging current is very small, and the storage battery has a certain effect on keeping the capacity of the battery.

The MCU is mainly added to monitor the charging voltage in real time, and when the charging voltage reaches a first set voltage, the charging current can be reduced by one step. The charging voltage is less than 20V and charging is carried out by 10A, when the charging voltage reaches 20.2V, the charging current is reduced from 10A to 8A for charging, when the charging voltage reaches 20.4V, the charging current is reduced from 8A to 4A for charging, when the charging voltage reaches 20.6V, the charging current is reduced from 4A to 2A for charging, when the charging voltage reaches 20.8V, the charging current is reduced from 2A to 0.5A for charging, and when the charging voltage reaches 21V, the charging current 0A represents that charging is finished.

Voltage of	Electric current
		<20V	10A
＝20.2V	10A→8A
		＝20.4V	8A→4A
＝20.6V	4A→2A
		＝20.8V	2A→0.5A
＝21V	0A

In addition, a switching circuit is added, so that the independent constant voltage function, the constant voltage function and the constant current function can be realized.

The main constant voltage circuit can output voltage for external 24V, the external output voltage can bear certain peak current, for example, in places with motors, the motor can instantly exceed rated current when being started or running under heavy load, and if the constant voltage and constant current circuit only needs to output current exceeding constant current, the output voltage is directly pulled.

To sum up, the utility model discloses constitute forward circuit 7 with U1 (UC 3845), output power when can providing charging, auxiliary power source is with flyback circuit 8 that U51 (GR 9210) constitutes, add secondary U44 LOD circuit and provide MCU power, constant voltage circuit is with constant voltage unit 92 that U115 TL431 constitutes, constant current unit 91 that constant current circuit constitutes with U110 (LM 321), add Q192 and Q129 and the peripheral constant voltage and constant voltage constant current switching circuit (namely: constant voltage constant current switching unit 92), utilize SW-1 button to select then output battery charging mode to charge, then MCU (CC SW) PIN output high potential makes Q129 action, Q192 follows the action, U4 and U2 two optical couplings all intervene U1 feedback, MCU (chang) PIN moves Q61 output signal secondary PC3, reflect to primary PC3 action Q2 and switch on and provide U1 IC operating voltage, just begin to export and charge, R27 is the cluster on the charging loop, the current can produce through resistance current pressure differential, this reverse PIN of introducing U3 of 100 of the input voltage. Compared with the positive input 4 pins of the U100, the constant current function of variable current is achieved. The signal of U100 positive input 4 feet is voltage through R55S and C42 by MCU (CC PWM) PIN generation PWM, and the magnitude of PWM duty cycle determines the magnitude of constant current.

The charging voltage is divided by a peripheral circuit composed of Q94 and Q95 through R95 and R96 and enters an MCU (ADC _ Bat) PIN to monitor the charging voltage at any time. When the charging voltage reaches the set level, the duty ratio is reduced, the relative current is reduced, the charging is stopped when the charging voltage reaches 21V and the high potential of the MCU (Changing om) PIN is changed into the low potential.

The SW-1 button is used for selecting a regular output constant voltage mode, then the MCU (CC SW) PIN outputs high potential to enable the Q129 and the Q192 not to act, the U4 optical coupling does not intervene in U1 feedback, the U2 optical coupling intervenes in U1 feedback, then the MCU (Changing om) PIN acts on the Q61 output signal secondary PC3, the primary PC3 is reflected to act Q2 to conduct and provide U1 IC working voltage, and the output is 24V constant voltage which can be mainly used under the condition that the instantaneous load exceeds 10A current.

Of course, the above description is only an exemplary embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes and modifications made by the constructions, features, and principles of the present invention in accordance with the claims of the present invention are intended to be included in the scope of the present invention.

Claims

1. A circuit for realizing constant voltage and constant current by utilizing switching technology is characterized by comprising: the transformer-based constant-voltage constant-current switching device comprises an AC input module (1), an EMI filtering module (2), an input rectifying and filtering module (3), a transformer module (4), an output rectifying and filtering module (5) and a DC output module (6) which are sequentially connected, wherein the transformer module (4) is connected with a forward excitation module (7) and a flyback module (8), the DC output module (6) is connected with a constant-voltage constant-current switching module (9), and the flyback module (8) and the constant-voltage constant-current switching module (9) are connected with a main control chip module (10).

2. The constant voltage and constant current circuit realized by using the switching technology according to claim 1, characterized in that: the constant voltage and constant current switching module (9) comprises a constant current unit (91), a constant voltage and constant current switching unit (92) connected with the constant current unit (91) and a constant voltage unit (93) connected with the constant voltage and constant current switching unit (92), the constant voltage unit (93) and the constant current unit (91) are respectively connected with the anode and the cathode of the DC output module (6), the constant current unit (91) is further connected with the flyback module (8) and the main control chip module (10), and the constant voltage and constant current switching unit (92) is further connected with the flyback module (8) and the main control chip module (10).

3. The circuit of claim 2, wherein the switching circuit is configured to: the constant voltage unit (93) and the constant current unit (91) are respectively connected with the forward module (7) through an optical coupler U2 and an optical coupler U4.

4. The constant voltage and constant current circuit realized by using the switching technology according to claim 3, characterized in that: the constant-voltage constant-current switching unit (92) comprises a resistor R50 connected with the optocoupler U4, an MOS tube Q192 connected with the resistor R50, an MOS tube Q129 and a resistor R49 connected with the MOS tube Q192, and a resistor R47 and a resistor R48 connected with the MOS tube Q129, wherein the resistor R47 is connected with a CC SW pin of the main control chip module (10), the resistor R49 and the MOS tube Q192 are connected with a +12V end of the flyback module (8), and the MOS tube Q129 and the resistor R48 are further connected with an SGND grounding end.

5. The circuit of claim 3, wherein the switching circuit is configured to: the constant voltage unit (93) comprises a resistor R41 and a resistor R43 which are connected with the anode of the DC output module (6), a resistor R44 and a resistor R45 which are connected with the resistor R43, a resistor R46 which are connected with the resistor R46, a capacitor C45 which is connected with the resistor R46, an optocoupler U2 which is connected with the resistor R41 and the capacitor C45, a voltage stabilizing source U115 which is connected with the optocoupler U2 and the resistor R43, and a resistor R42 which is connected in parallel on the optocoupler U2, wherein the voltage stabilizing source U115, the resistor R44 and the resistor R45 are also connected with an SGND grounding end.

6. The constant voltage and constant current circuit realized by using the switching technology according to claim 3, characterized in that: the constant current unit (91) comprises a single-path operational amplifier U100A, a resistor R52 and a resistor R51 which are connected with pins 3 in the single-path operational amplifier U100A, a capacitor C113 which is connected with pins 4 in the single-path operational amplifier U100A and the resistor R51, a resistor R55A and a capacitor C42 which are connected with pins 1 in the single-path operational amplifier U100A, wherein the pins 4 of the single-path operational amplifier U100A are also connected with the optocoupler U4, the negative pole of the single-path operational amplifier U100A, the resistor R55 and the capacitor C42 are also connected with an SGND grounding end, the resistor R55A is connected with a PWM CC (pulse width modulation) pin of the main control chip module (10), and the positive pole of the single-path operational amplifier U100A is connected with a +12V end of the flyback module (8).

7. The circuit of claim 6, wherein the switching circuit is configured to: and the pin 1 in the single-path operational amplifier U100A is connected with the pin +2.5V of the main control chip module (10) through a resistor R54 and is connected with the pin +5V of the main control chip module (10) through a resistor 53.

8. The constant voltage and constant current circuit realized by using the switching technology according to claim 3, characterized in that: an MOS tube Q61 is arranged in the flyback module (8), the MOS tube Q61 is connected with the flyback module (7) through an optocoupler PC3, and the MOS tube Q61 is also connected with a Charging on pin of the main control chip module (10) through a resistor R65; and the optocoupler PC3 is connected through an MOS (metal oxide semiconductor) tube Q2 to provide the working voltage of the chip U1 in the forward module (7).

9. The constant voltage and constant current circuit implemented by using the switching technique as claimed in any one of claims 1 to 8, wherein: and the positive electrode of the DC output module (6) is also connected with a voltage monitoring module (61).

10. The circuit of claim 9, wherein the switching circuit is configured to: and a MODDE pin of the main control chip module (10) is connected with a SW-1 switch module (101) for switching between a constant voltage charging mode and a constant current charging mode.