CN204131110U - Based on the battery system anti-surge circuit of discrete elements - Google Patents

Abstract

Based on the battery system anti-surge circuit of discrete elements, it is connected on the input that module is connected with anode, comprise the metal-oxide-semiconductor of the input being connected to module, described metal-oxide-semiconductor is connected with RC circuit, described RC circuit connects to form with the second resistant series after being connected with the first resistor coupled in parallel by electric capacity again, described electric capacity is connected with the grid of described metal-oxide-semiconductor with the series connection end of the second resistance with the first resistance, the other end of described electric capacity and the first resistance is connected with the source electrode of described metal-oxide-semiconductor and connects with the input be connected with anode of module, the input be connected with battery cathode of the other end of described second resistance and module connects.The utility model improves system reliability, considerably increases battery system efficiency, convenient for maintaining.

Description

Anti-surge circuit for battery system based on discrete components

technical field

The utility model relates to a battery system anti-surge circuit based on discrete components.

Background technique

Hot swapping refers to inserting modules, cards or subsystems into the system without affecting the operation of the system or the operation of the inserted modules, cards or subsystems when the system is powered on.

Figure 1 shows the hot swap process, where the left side represents the power supply system, generally there is a large capacitor at the output end of the power supply, and the right side represents the module, and the input end of the module also has a capacitor. Before the module is inserted into the system, the input capacitor is not charged. When the module is inserted into the system, it is equivalent to connecting two large capacitors with different terminal voltages in parallel. According to Kirchhoff's law, there will be a large instantaneous current to the module. The group input capacitor is charged. This large instantaneous current may cause abnormal system power supply voltage. If the lead wire is long, there will be a large lead inductance, which will cause voltage oscillation, and the voltage spike may permanently damage the module. When the equivalent RLC value reaches a certain range, the peak voltage at the input terminal of the module will reach twice the rated input voltage, but the maximum voltage range of the module (reserved for the input voltage range design) is often not so large, which causes damage to the module damage.

There are many traditional solutions, such as connecting a thermistor in series between the power supply system and the module, or connecting a varistor or TVS in parallel at both ends of the power supply system. Only one of them is introduced here, that is, an NTC thermistor in series, such as As shown in Figure 2, the thermistor device is connected in series to the input end of the electronic equipment, which plays the role of anti-surge when the connector is connected. In this way, when the module is replaced, the work of the system will not be affected by the surge, which improves the reliability.

For products applied to batteries, because the battery is equivalent to a very large capacitor, the above-mentioned problems will also occur. The existing solution is to connect an NTC thermistor in series between the battery and the module, or replace the ceramic capacitor at the input end of the module with an electrolytic capacitor, because the inrush current of the ceramic capacitor is larger, or the input end of the module is connected to a ceramic capacitor Connect a small resistor in series.

If an NTC thermistor is connected in series between the battery and the module, the NTC will have a large resistance, and if the current of the module is large, there will be a large loss in the NTC, which will greatly increase the efficiency of the battery capacity. reduce. The series thermistor also affects the voltage detection accuracy of the module, and some battery systems require high voltage detection accuracy. For example, assuming that the resistance of the NTC is 30mΩ after normal operation, and the working current of the module is 2A, then the voltage on the NTC thermistor For some battery systems, the value of this sampling error is unacceptable. Also, if the input terminal of the module is replaced by an electrolytic capacitor, because some battery systems are high-frequency switching converters, the high-frequency filtering effect of the electrolytic capacitor is very poor; if the input terminal of the module is replaced by a ceramic capacitor in series with a small resistor , then the filtering effect will be affected, and the absorbing ability of the switching ripple will become worse.

Contents of the invention

The utility model provides a battery system anti-surge circuit based on discrete components, which improves system reliability, greatly increases battery system efficiency, and facilitates maintenance.

The technical scheme that the utility model adopts is:

The anti-surge circuit of the battery system based on discrete components is connected to the input end of the module connected to the positive pole of the battery. It is characterized in that it includes a MOS tube connected to the input end of the module, and an RC circuit is connected to the MOS tube. The RC circuit is composed of a capacitor connected in parallel with the first resistor and then connected in series with the second resistor, the capacitor, the serial end of the first resistor and the second resistor are connected to the gate of the MOS transistor, and the capacitor The other end of the first resistor is connected to the source of the MOS tube and connected to the input end of the module connected to the positive pole of the battery, and the other end of the second resistor is connected to the input end of the module connected to the negative pole of the battery . When the module is connected to the battery, that is, at the initial stage of power-on, it can be known from the characteristics of the RC circuit that the voltage of the MOS tube Vgs is small, and the resistance between the drain and source of the MOS tube is large, thereby limiting the inrush current. By controlling the RC circuit The value can control the voltage rise curve of Vgs, and the time required for Vgs to rise to make the MOS tube completely turn on is equal to the time when the capacitor voltage at the input terminal of the module is close to the battery voltage, so that the instantaneous surge current can be limited to A lower level, thereby realizing a high-efficiency battery system with anti-surge technology, improving system reliability, greatly increasing battery system efficiency, and facilitating maintenance.

Further, a Zener diode is connected in parallel between the gate and source of the MOS transistor, the anode of the Zener diode is connected to the gate of the MOS transistor, and its cathode is connected to the source. The Zener diode can protect the MOS tube when the voltage at the input terminal is high, and can limit the Vgs of the MOS tube within a certain range without damaging the MOS tube.

Further, the battery is formed by a plurality of batteries connected in series, and the input end of the module connected to the positive pole of each battery is provided with an anti-surge circuit.

Further, the other end of the second resistor is connected to the input end of the module that is connected to the negative pole of this battery or other batteries. When the voltage of a battery is not high enough, the divided voltage does not reach the turn-on voltage of the MOS tube, and the other end of the second resistor can be connected to the input end of the module connected to the negative pole of other batteries to increase the voltage. The voltage of the MOS tube to reach its turn-on voltage.

The beneficial effect of the utility model: by connecting the RC circuit on the MOS tube to control the voltage between the grid and the source, to control the conduction or shutdown of the MOS tube, to limit the surge current connected between the module and the battery, and to improve System reliability, greatly increased battery system efficiency, and easy maintenance.

Description of drawings

Figure 1 is a schematic diagram of the hot swap process.

FIG. 2 is a schematic structural diagram of a traditional anti-surge technology.

Fig. 3 is a structural schematic diagram of the utility model.

Fig. 4 is another structural schematic diagram of the utility model.

Fig. 5 is a schematic diagram of the third structure of the utility model.

Detailed ways

The utility model will be further described below in conjunction with specific embodiments, but the utility model is not limited to these specific embodiments. Those skilled in the art should realize that the present invention covers all alternatives, improvements and equivalents that may be included within the scope of the claims.

Embodiment one

Referring to Fig. 3, the anti-surge circuit of the battery system based on discrete components is connected to the input end of the module 1 connected to the positive pole of the battery 2, and includes a MOS transistor Q2 connected to the input end of the module 1, and the MOS transistor Q2 An RC circuit is connected, and the RC circuit is composed of a capacitor C2 connected in parallel with the first resistor R2 and then connected in series with the second resistor R4, and the serial terminal of the capacitor C2, the first resistor R2, and the second resistor R4 is connected to the The gate of the MOS transistor Q2 is connected, the other end of the capacitor C2 and the first resistor R2 are connected to the source of the MOS transistor Q2 and connected to the input terminal of the module 1 connected to the positive pole of the battery 2, and the first The other end of the second resistor R4 is connected to the input end of the module 1 connected to the negative pole of the battery 2 . The role of the first resistor R2 is to protect the situation of multiple plugging and unplugging. Since the value of the capacitor C2 is very small, when the connector is unplugged, the charge accumulated in the capacitor C2 can be quickly consumed by the first resistor R2. In this way, the MOS transistor Q2 is quickly turned off, preventing the MOS transistor Q2 from having a through phenomenon during repeated plugging and unplugging.

The specific analysis of the circuit in this embodiment is as follows: According to i*t=c*v, it can be known

(1)

A known

(2)

(3)

(4)

Substituting equation (4) into (1) shows that

(5)

It can be known from the above formula

(6)

According to the above analysis, when the module 1 is connected to the battery 2, that is, at the initial stage of power-on, the characteristics of the RC circuit show that the Vgs voltage of the MOS transistor Q2 is small, and the resistance between the drain and the source of the MOS transistor Q2 is very large, thereby limiting Inrush current, by controlling the value of the RC circuit, the voltage rise curve of Vgs can be controlled, and the time required for Vgs to rise to the point where the MOS transistor Q2 is fully turned on is equal to when the voltage of the input capacitor C4 of module 1 is close to the voltage of battery 2 Time, so that the instantaneous surge current can be limited to a low level, thereby realizing a high-efficiency battery system with anti-surge technology, improving system reliability, greatly increasing battery system efficiency, and facilitating maintenance. The battery 2 in this embodiment is composed of n batteries, and n can be 1, 2, 3. . .

In this embodiment, a Zener diode D2 is connected in parallel between the gate and source of the MOS transistor Q2, the anode of the Zener diode D2 is connected to the gate of the MOS transistor Q2, and the cathode is connected to the source. The Zener diode D2 can protect the MOS transistor Q2 when the voltage at the input terminal is high, and can limit the Vgs of the MOS transistor Q2 within a certain range without damaging the MOS transistor Q2.

The utility model controls the voltage between the gate and the source of the MOS transistor Q2 by connecting an RC circuit to control the conduction or shutdown of the MOS transistor Q2 to limit the surge current connected between the module 1 and the battery 2 .

Embodiment two

Referring to Fig. 4, the difference between this embodiment and the first embodiment is that the battery 2 is formed by a plurality of batteries 2 connected in series, and the input end of the module 1 connected to the positive pole of each battery 2 is equipped with anti-wave surge circuit. Each battery 2 in this embodiment is composed of n batteries, and n can be 1, 2, 3 . . . There are three input branches in the module 1 of this embodiment, as long as two circuits are selected to design anti-surge circuits, it is possible to prevent the possibility of large current loops at the instant of connector connection. The anti-surge technology is implemented by connecting a MOS transistor Q1 or Q2 in series between the VM and VP terminals of the battery 2 and the module 1, and the MOS transistor Q1 or Q2 controls its working state through discrete components respectively. Because the structure is symmetrical, if the batteries above VP continue to be connected in series, our anti-surge circuit only needs to be added one by one. The rest of the structures and functions are the same as those in Embodiment 1.

Embodiment three

Referring to FIG. 5 , the difference between this embodiment and the second embodiment is that the other end of the second resistor R3 or R4 is connected to the input end of the module 1 that is connected to the negative pole of other batteries 2 . When the voltage of a battery 2 is not high enough, the divided voltage does not reach the turn-on voltage of the MOS tube, and the other end of the second resistor R3 or R4 can be connected to the negative pole of the module 1 and other batteries 2 The input terminal is connected to increase the voltage of the MOS tube to reach its turn-on voltage. Taking R3 as an example, one end is connected to the capacitor C1, and the other end is connected to the negative pole of the next battery 2, that is, the VN end. If this is not enough to completely open the MOS transistor Q1, then the other end of R3 is connected to the next battery. The negative pole of battery 2, that is, the VB terminal, and so on until the MOS tube Q1 can be completely turned on; taking R4 as an example, one end is connected to the capacitor C2, and the other end is connected to the negative pole of the next battery 2, as shown in the figure In the VB side. If this is not enough to completely open the MOS tube Q2, then the other end of R4 is connected to the negative pole of the next battery, and so on. Because the structure is symmetrical, if the batteries above VP continue to be connected in series, our anti-surge circuit only needs to be added one by one. All the other structures and functions are the same as those in Embodiment 2.

Claims (4)

1. based on the battery system anti-surge circuit of discrete elements, it is connected on the input that module is connected with anode, it is characterized in that: the metal-oxide-semiconductor comprising the input being connected to module, described metal-oxide-semiconductor is connected with RC circuit, described RC circuit connects to form with the second resistant series after being connected with the first resistor coupled in parallel by electric capacity again, described electric capacity is connected with the grid of described metal-oxide-semiconductor with the series connection end of the second resistance with the first resistance, the other end of described electric capacity and the first resistance is connected with the source electrode of described metal-oxide-semiconductor and connects with the input be connected with anode of module, the input be connected with battery cathode of the other end of described second resistance and module connects.

2., as claimed in claim 1 based on the battery system anti-surge circuit of discrete elements, it is characterized in that: a voltage stabilizing didoe in parallel between the grid source electrode of described metal-oxide-semiconductor, the anode of voltage stabilizing didoe is connected with the grid of metal-oxide-semiconductor, and its negative pole is connected with source electrode.

3. as claimed in claim 1 or 2 based on the battery system anti-surge circuit of discrete elements, it is characterized in that: described battery is connected by multiple batteries to be formed, and the input that described module is connected with every batteries positive pole is equipped with anti-surge circuit.

4. as claimed in claim 3 based on the battery system anti-surge circuit of discrete elements, it is characterized in that: the input be connected with this batteries or other batteries negative poles of the other end of described second resistance and described module connects.