CN211456768U

CN211456768U - High-voltage boosting charger battery reverse connection protection circuit

Info

Publication number: CN211456768U
Application number: CN202020454941.3U
Authority: CN
Inventors: 王虎刚
Original assignee: Xinlu Technology Suzhou Co Ltd
Current assignee: Xinlu Technology Suzhou Co Ltd
Priority date: 2020-04-01
Filing date: 2020-04-01
Publication date: 2020-09-08
Anticipated expiration: 2030-04-01

Abstract

The utility model discloses a high pressure charger battery reversal protection circuit that steps up, it includes: the charging power supply module comprises a power supply, an inductor connected with the power supply and a diode connected with the inductor, and is used for providing charging voltage; the control protection module comprises a controller and a first NMOS tube, wherein the first NMOS tube is an LDMOS tube, the control protection module is connected between an inductor and a diode, the connection point is a SW node, the control protection module further comprises a first switch module connected between the SW node and the inductor and a second switch module connected between the first NMOS tube and the SW node, and under the condition that a battery is reversely connected, reverse current is completely eliminated no matter reverse current flows from a power supply to the SW node through the inductor or reverse current flows from a ground wire to the SW node through a source electrode of the first NMOS tube.

Description

High-voltage boosting charger battery reverse connection protection circuit

Technical Field

The utility model relates to a high pressure charger battery that steps up joins conversely protection circuit.

Background

The general step-down charger structure is shown in fig. 1, and when the battery is reversely connected, the protection of the charger is realized through BODY switching. This configuration is also the most commonly used configuration at present. But is only applicable to a single lithium battery step-down charging structure.

With the increasing demand of large-capacity batteries, the voltage-reduction structure charger has been unable to meet the demand of large-capacity charging. For the charging of a large-capacity battery, a structure of a Boost may be used to charge the series battery pack. As shown in fig. 2-3, the high-voltage charging structure is explained by taking 3 batteries as an example, generally, a large-capacity battery is formed by connecting single batteries in series, and the maximum voltage at the point SW is: vsw is 3 BAT +0.7 up to about 15V, and all NMOS of the 3-node boost chargers use a high voltage LDMOS of 15V. However, in the conventional high-voltage integrated circuit process of the LDMOS, the Body of the NMOS cannot be selected, and the Body can only be connected with the Source of the NMOS. However, when the battery is reverse connected, the current path from the inductor VIN to BAT is direct due to the inherent structural defect of boosting. The body diode of the NMOS will turn on and cannot be turned off completely. Consequently, when the battery is reverse connected, two uncontrollable currents flow to the negative electrode of the BAT battery pack, as shown in fig. 3. 1. From the power supply VIN via inductor L1 to the SW node, which reaches the reverse current IREV1 of the BAT cathode via diode D1. 2. From GND through the Body diode of NMOS to SW node, which is reverse current IREV2 through diode D1. 3. The existence of these 2 path currents, whether to the VIN power supply system or the charger chip itself, can cause significant damage.

And the existence of the self inductance of the boost structure cannot realize protection by the selection of Body like the common buck structure. How to protect the boosting structure from being damaged under the condition that the battery is reversely connected is a problem which needs to be solved urgently at present.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a high pressure charger battery reversal protection circuit that steps up who treats rechargeable battery and charging circuit and be connected thoroughly cuts off when detecting rechargeable battery reversal.

In order to solve the technical problem, the utility model adopts the following technical scheme: a high voltage boost charger battery reverse connection protection circuit, comprising:

the charging power supply module comprises a power supply, an inductor connected with the power supply and a diode connected with the inductor, and is used for providing charging voltage;

the control protection module comprises a controller and a first NMOS (N-channel metal oxide semiconductor) tube, wherein the first NMOS tube is an LDMOS (laterally diffused metal oxide semiconductor) tube, the control protection module is connected between an inductor and a diode, the connection point is an SW (switch element) node,

the control protection module further comprises a first switch module connected between the SW node and the inductor and a second switch module connected between the first NMOS transistor and the SW node,

the control protection module is used for detecting the positive and negative connection state of the battery, controlling the first switch module and the second switch module to be connected to form a charging loop when the battery to be charged is positively connected, and controlling the first switch module and the second switch module to be disconnected when the battery is reversely connected so as to cut off the charging loop of the charging power supply to the battery to be charged and the loop of the charging power supply which is input to the battery to be charged through the first NMOS tube by the ground wire.

Preferably, the first switch module includes a first PMOS transistor which is an LDMOS transistor, and the gate of the first PMOS transistor is connected to the controller, the source of the first PMOS transistor is connected to the inductor, and the drain of the first PMOS transistor is connected to the SW node.

Preferably, the second switch module includes a second NMOS transistor, a gate of which is connected to the controller, a drain of which is connected to the drain of the first NMOS transistor, and a source of which is connected to the SW node.

Furthermore, the second switch module further comprises a resistor, two ends of which are respectively connected with the gate and the source of the second NMOS transistor, and a second PMOS transistor, the gate of which is connected with the controller and the drain of which is connected with the gate of the second NMOS transistor, the source of the second PMOS transistor is connected with the power supply, and the second NMOS transistor and the second PMOS transistor are both LDMOS transistors.

The beneficial effects of the utility model reside in that:

1) in the case of reverse battery connection, complete elimination of reverse current flowing from the power supply to the SW node through the inductor or from the ground to the SW node through the source of the first NMOS transistor is achieved.

2) No matter how many load batteries are, the structural circuit can meet the requirement of high-voltage charging of a system and can realize self-protection, and only the withstand voltage of the NMOS and the PMOS is required to meet the requirement of the batteries.

3) The NMOS and the PMOS both use the MOSFET, so that the integration is easy, and meanwhile, compared with the case that the Diode is used independently, the conduction loss of the system is effectively reduced, the charging efficiency of the system is greatly improved, and the output power is further improved under the condition of the same chip area.

4) The structure is particularly designed for a boosting high-power charger chip, is easy to integrate, meets high-voltage high-power charging, and provides effective protection for the charger under the condition that the battery is reversely connected.

Drawings

FIGS. 1-3 are schematic diagrams of a prior art charging circuit;

fig. 4 is a schematic structural diagram of a charging circuit according to a first embodiment;

fig. 5 is a schematic structural diagram of a charging circuit in the second embodiment.

Detailed Description

The invention will be described in detail below with reference to an exemplary embodiment shown in the drawings:

example one

As shown in fig. 4, the reverse battery protection circuit of the high-voltage boost charger includes:

a charging power supply module comprising a power supply (VIN), an inductor (L1) connected to the power supply, and a diode (D1) connected to the inductor for providing a charging voltage;

a control protection module including a controller and a first NMOS transistor (NMOS1),

the control protection module is connected between an inductor (L1) and a diode (D1), the connection point is an SW node,

the control protection module further comprises a first PMOS (PMOS) tube (PMOS) connected between the SW node and the inductor, a second NMOS tube (NMOS2), a resistor and a second PMOS tube (PMOS2), wherein the grid electrode of the first PMOS tube is connected with the controller, the source electrode of the first PMOS tube is connected with the inductor, the drain electrode of the first PMOS tube is connected with the SW node, the grid electrode of the second NMOS tube is connected with the drain electrode of the second PMOS tube, the drain electrode of the second PMOS tube is connected with the drain electrode of the first NMOS tube, the source electrode of the second PMOS tube is connected with the SW node, two ends of the resistor are respectively connected with the grid electrode and the source electrode of the second NMOS tube, the grid electrode of the second PMOS tube is connected with the controller, the drain electrode of the second. P _ DRV, N _ DRV1 and N _ DRV2 control 3 high voltage MOS synchronously, and since the second NMOS transistor is floating, the driving structure of N _ DRV2 needs special handling, and at the same time, the state of the switch when VIN is 0 needs special consideration. The last stage of driving structure of the second NMOS tube is half-edge driving, and the opening (Turn ON) of the second NMOS tube is controlled by a second PMOS tube. The Turn-OFF (Turn-ON) of the second NMOS transistor is realized by R1, and another important function of R1 is that the second NMOS transistor is in a Turn-OFF (Turn-OFF) state by default when the power is not enabled.

The control principle of the control protection module is as follows:

the battery is connected and output to be a high-voltage structure, the first PMOS tube, the second PMOS tube, the first NMOS tube and the second NMOS tube are all LDMOS tubes, the first NMOS tube and the second NMOS tube are in a Back-to-Back structure, and the requirement of high voltage of a system is met.

When the battery is normally connected, the system is normally charged, and the first PMOS tube is kept in a closed (ON) state all the time. The first NMOS tube and the second NMOS tube are periodically switched ON and OFF (OFF) according to the requirement of the boost charging system.

When the reverse connection of the battery is detected, the first PMOS tube and the first NMOS tube are simultaneously disconnected (OFF). Compared with the original boosting system: due to the addition of the high-voltage first NMOS tube and the high-voltage first PMOS tube, the first PMOS tube is disconnected (OFF) under the condition that the battery is reversely connected, and the Body diode of the first PMOS tube cannot be conducted. The body diode of the first NMOS tube and the body diode of the second NMOS tube form a body-to-body structure, and the reverse path current of the first NMOS tube and the second NMOS tube is completely cut off. Under the condition of reverse connection of the battery, the structure thoroughly blocks reverse current entering the Battery (BAT) from a power supply and a ground wire, and can effectively protect a charger chip from being burnt.

Example two

As shown in fig. 5, the reverse battery protection circuit of the high-voltage boost charger includes:

the charging power supply module is used for providing charging voltage and comprises a power supply (VIN), an inductor (L1), a switch (K1) and a first diode (D1) which are sequentially connected, wherein the anode of the first diode is connected with the switch, and the cathode of the first diode is connected with a Battery (BAT) group;

and the control protection module comprises a controller, an NMOS (N-channel metal oxide semiconductor) tube and a second diode (D2), wherein the grid electrode of the NMOS tube is connected with the controller, the drain electrode of the NMOS tube is connected with the cathode of the second diode, the source electrode of the NMOS tube is grounded, the anode of the second diode is connected between the switch and the anode of the first diode, and the connection point is a node (SW).

The advantages and disadvantages of the circuit in this embodiment are as follows: the problem of body diode current that passes through the NMOS pipe from the ground wire when can solve the battery to a certain extent and connect conversely, but because the existence of No. two diodes, under the system normal charging condition, No. two diodes have very big conduction loss to whole boost system's efficiency will greatly reduced.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose of the embodiments is to enable people skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A high voltage boost charger battery reverse connection protection circuit, comprising:

the control protection module comprises a controller and a first NMOS tube, wherein the first NMOS tube is an LDMOS tube,

the control protection module is connected between the inductor and the diode, the connection point is an SW node,

the method is characterized in that: the control protection module further comprises a first switch module connected between the SW node and the inductor and a second switch module connected between the first NMOS transistor and the SW node,

2. The reverse battery protection circuit of a high-voltage boost charger according to claim 1, characterized in that: the first switch module comprises a first PMOS tube which is an LDMOS tube, the grid electrode of the first PMOS tube is connected with the controller, the source electrode of the first PMOS tube is connected with the inductor, and the drain electrode of the first PMOS tube is connected with the SW node.

3. The reverse battery protection circuit of a high-voltage boost charger according to claim 1, characterized in that: the second switch module comprises a second NMOS tube, wherein the grid electrode of the second NMOS tube is connected with the controller, the drain electrode of the second NMOS tube is connected with the drain electrode of the first NMOS tube, and the source electrode of the second NMOS tube is connected with the SW node.

4. The reverse battery protection circuit of a high-voltage boost charger according to claim 3, characterized in that: the second switch module further comprises a resistor and a second PMOS tube, wherein two ends of the resistor are respectively connected with the grid electrode and the source electrode of the second NMOS tube, the grid electrode of the second PMOS tube is connected with the controller, the drain electrode of the second PMOS tube is connected with the grid electrode of the second NMOS tube, the source electrode of the second PMOS tube is connected with the power supply, and the second NMOS tube and the second PMOS tube are LDMOS tubes.