Intelligent high-side switch chip capable of realizing reverse power protection and protection method

Abstract

The present invention relates to an intelligent high-side switch chip capable of realizing reverse power supply protection and a protection method. The chip comprises a charge pump, a GATE driving module, a reverse protection resistor and a reverse power supply protection circuit; the reverse power supply protection circuit comprises a first driving current generating unit, a second driving current generating unit, a current pull-up unit and a current pull-down unit; the current pull-up unit is used to pull up the driving voltage of the GATE driving module; the current pull-down unit is used to close the pull-down current of the GATE driving module. When the power supply of the intelligent high-side switch chip is reversely connected, a voltage drop is generated on the reverse protection resistor, and the voltage drop controls the opening of a power MOS tube through the first driving current generating unit and the second driving current generating unit connected in parallel. Then, the power consumption of the power MOS tube when the power supply is reversely connected is the same as that when the power supply is positively connected and when the power MOS tube is forwardly conducted, thereby protecting the power MOS tube, and solving the technical problem that the power MOS tube is easily burned when the power supply of the existing intelligent high-side switch chip is reversely connected.

Description

Technical Field

[0001] The present invention relates to an intelligent high-side switch chip and a reverse power protection method, and in particular to an intelligent high-side switch chip capable of realizing reverse power protection and a reverse power protection method. Background Art

[0002] The intelligent high-side switch chip is an automotive electronic device used to replace relays or fuses. It is generally placed on the high side of a branch of the automotive power supply. While providing switching power, it can also realize self-detection.

[0003] Figure 1 It is the system structure and pin diagram of the intelligent high-side switch chip. Figure 1 In the circuit, the charge pump is used to monitor the dynamic situation of the load, and the resistor Rbb is a reverse protection resistor. Under normal circumstances, the VBB pin is connected to the positive pole of the power supply and the IN pin or IS pin is connected to the signal ground. If the power supply is reversed during use, that is, the VBB pin is connected to the signal ground and the IN pin or IS pin is connected to the positive pole of the power supply, the load current flows through the body diode in the power MOS tube, generating a very large power loss on the power MOS tube, causing the temperature rise of the power MOS tube to rise sharply, and it is easy to burn the power MOS tube. Summary of the invention

[0004] The purpose of the present invention is to provide an intelligent high-side switch chip and a protection method capable of realizing reverse power supply protection, which solves the technical problem that the existing intelligent high-side switch chip is easy to burn out the power MOS tube when the power supply is reversely connected.

[0005] The technical solution of the present invention is:

[0006] An intelligent high-side switch chip capable of realizing reverse power supply protection comprises a VBB pin, an IN pin, an IS pin, an OUT pin, a charge pump, a GATE driving module and a reverse protection resistor Rbb; the driving module comprises a power MOS tube; the gate of the power MOS tube is connected to the output end of the charge pump, the source thereof is connected to the OUT pin, and the drain thereof is connected to the VBB pin and one end of the reverse protection resistor Rbb; the special feature of the invention is that it also comprises a reverse power supply protection circuit; the reverse power supply protection circuit comprises a first driving current generating unit, a second driving current generating unit, a current pull-up unit and a current pull-down unit; the current pull-up unit is used to pull up the driving voltage of the GATE driving module; the current pull-down unit is used to turn off the pull-down current of the GATE driving module; the first driving current generating unit comprises a first resistor R1, a first voltage regulator tube D1, a sixth diode D6, a fifth diode D5, a first PMOS tube P1 and a third PMOS tube P3; the second driving current generating unit comprises a second resistor R2, a second voltage regulator tube D2, an eighth diode D8, a seventh diode D7, a second PMOS tube P2 and a fourth PMOS tube P4; the One end of the first resistor R1 and one end of the second resistor R2 are connected to the other end of the reverse protection resistor Rbb; the positive electrode of the first voltage regulator D1 is connected to the other end of the first resistor R1, the gate of the first PMOS tube P1 and the gate of the third PMOS tube P3, and the negative electrode thereof is connected to the source of the first PMOS tube P1 and the source of the third PMOS tube P3; the negative electrode of the sixth diode D6 is connected to the other end of the reverse protection resistor Rbb, and the positive electrode thereof is connected to the negative electrode of the fifth diode D5; the positive electrode of the fifth diode D5 is connected to the drain of the first PMOS tube P1 and the IN pin; the second voltage regulator D2 The positive electrode of the eighth diode D8 is connected to the other end of the second resistor R2, the gate of the second PMOS tube P2 and the gate of the fourth PMOS tube P4, and the negative electrode thereof is connected to the source of the second PMOS tube P2 and the source of the fourth PMOS tube P4; the negative electrode of the eighth diode D8 is connected to the other end of the reverse protection resistor Rbb, and the positive electrode thereof is connected to the negative electrode of the seventh diode D7; the positive electrode of the seventh diode D7 is connected to the drain of the second PMOS tube P2 and the IS pin; the drain of the third PMOS tube P3, the drain of the fourth PMOS tube P4, the input end of the current pull-up unit, and the input end of the current pull-down unit are connected as one point.

[0007] The current pull-up unit includes a third diode D3 and a first switch tube N1; the current pull-down unit includes a fourth diode D4, a second switch tube N2, a third resistor R3, a fifth switch tube N5 and a sixth switch tube N6; the drain of the third PMOS tube P3, the drain of the fourth PMOS tube P4, the anode of the third diode D3 and the anode of the fourth diode D4 are connected as a point; the cathode of the third diode D3 is connected to the drain of the first switch tube N1; the gate and source of the first switch tube N1 are connected to the gate of the power MOS tube; the cathode of the fourth diode D4 is connected to the drain of the second switch tube N2; the gate and source of the second switch tube N2 are connected to the gate of the fifth switch tube N5; the drain of the fifth switch tube N5 is connected to the gate of the sixth switch tube N6 and the gate of the power MOS tube; the drain of the sixth switch tube N6 is connected to the gate of the power MOS tube; the source of the fifth switch tube N5 and the source of the sixth switch tube N6 are connected to the OUT pin; and the two ends of the third resistor are respectively connected to the source and gate of the fifth MOS tube.

[0008] In order to reduce the area of ​​the circuit board and simplify the circuit design, the first switch tube N1 and the second switch tube N2 are the same, both of which are depletion-type field effect tubes or JFET field effect tubes.

[0009] To simplify the design and manufacturing process, the fifth switch tube N5 and the sixth switch tube N6 are the same, both of which are MOS tubes.

[0010] In order to quickly turn on the sixth switch tube N6, the drain of the fifth switch tube N5 is connected to the gate of the power MOS tube through the fourth resistor R4.

[0011] For current limiting considerations, the drain of the sixth switch tube N6 is connected to the gate of the power MOS tube via the fifth resistor R5.

[0012] The above-mentioned protection method of the intelligent high-side switch chip is special in that:

[0013] When the power supply of the intelligent high-side switch chip is positively connected, the current pull-down unit is turned off, the power MOS tube in the GATE driver module is turned on, and the charge pump provides current to the GATE driver module;

[0014] When the power supply of the intelligent high-side switch chip is reversely connected, the reverse protection resistor Rbb and the fifth diode D5 and the sixth diode D6, the seventh diode D7 and the eighth diode D8 form an internal reverse voltage source, and the first switch tube N1 and the second switch tube N2 act as current sources to provide voltage to the GATE drive module; the power MOS tube in the GATE drive module is cut off, and the sixth switch tube N6 of the current pull-down unit is turned off; the reverse power supply generates a voltage drop Vbb1 on the reverse protection resistor Rbb, and then on the basis of this voltage drop Vbb1, the power MOS tube is controlled to be turned on through the first drive current generating unit and the second drive current generating unit connected in parallel.

[0015] Specifically, if the IN pin is reversely connected to +5V, there is a voltage drop of 0.7V on the first voltage regulator D1, which causes the first PMOS tube P1 and the third PMOS tube P3 to be turned on; the current of the first PMOS tube P1 and the third PMOS tube P3 flows through the fourth diode D4 and the second switch tube N2, so that the fifth switch tube N5 is turned on to turn off the sixth switch tube N6, thereby turning off the GATE pull-down current; at the same time, the current of the first PMOS tube P1 and the third PMOS tube P3 passes through the third diode D3 and the first switch tube N1, pulling up the GATE drive voltage, and the GATE drive voltage causes the power MOS tube to be turned on.

[0016] Alternatively, if the IS pin is reversely connected to +5V, there is a voltage drop of 0.7V on the second voltage regulator D2, which turns on the second PMOS tube P2 and the fourth PMOS tube P4; the current of the second PMOS tube P2 and the fourth PMOS tube P4 flows through the fourth diode D4 and the second switch tube N2, so that the fifth switch tube N5 is turned on to turn off the sixth switch tube N6, thereby turning off the GATE pull-down current; at the same time, the current of the second PMOS tube P2 and the fourth PMOS tube P4 passes through the third diode D3 and the first switch tube N1, pulling up the GATE drive voltage, and the GATE drive voltage turns on the power MOS tube.

[0017] Beneficial effects of the present invention:

[0018] 1. The present invention adds a reverse power protection circuit in the intelligent high-side switch chip. The circuit turns on the power MOS tube when the power supply is reversely connected. Since the voltage drop of the power MOS tube is small after it is turned on, the power consumption of the power MOS tube when the power supply is reversely connected is the same as the power consumption of the power MOS tube when the power supply is positively connected and when it is forwardly turned on, thereby protecting the power MOS tube.

[0019] 2. The reverse power protection circuit added by the present invention does not affect the normal operation of the intelligent high-side switch chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the internal structure and external pins of an existing intelligent high-side switch chip;

[0021] Figure 2 It is a circuit schematic diagram of a reverse power protection circuit in the intelligent high-side switch chip of the present invention. DETAILED DESCRIPTION

[0022] See also Figure 2The present invention can realize the intelligent high-side switch chip of reverse power protection, including a charge pump, a GATE driving module, a reverse protection resistor Rbb and a reverse power protection circuit, and the chip is provided with a VBB pin, an IN pin, an IS pin and an OUT pin. The GATE driving module includes a power MOS tube, the output of the charge pump is connected to the gate of the power MOS tube, the source of the power MOS tube is connected to the OUT pin, and the drain thereof is connected to the VBB pin; one end of the reverse protection resistor Rbb is connected to the VBB pin.

[0023] The reverse power supply protection circuit includes a first drive current generating unit, a second drive current generating unit, a current pull-up unit and a current pull-down unit; the first drive current generating unit includes a first resistor R1, a first voltage regulator tube D1, a sixth diode D6, a fifth diode D5, a first PMOS tube P1 and a third PMOS tube P3; the second drive current generating unit includes a second resistor R2, a second voltage regulator tube D2, an eighth diode D8, a seventh diode D7, a second PMOS tube P2 and a fourth PMOS tube P4; the current pull-up unit includes a third diode D3 and a first switch tube N1; the current pull-down unit includes a fourth diode D4, a second switch tube N2, a third resistor R3, a fifth switch tube N5 and a sixth switch tube N6; the first switch tube N1 and the second switch tube N2 are preferably field effect tubes.

[0024] The specific connection relationship of the reverse power protection circuit is as follows:

[0025] One end of the first resistor R1 and one end of the second resistor R2 are connected to the other end of the reverse protection resistor Rbb; the positive electrode of the first voltage regulator tube D1 is connected to the other end of the first resistor R1, the gate of the first PMOS tube P1 and the gate of the third PMOS tube P3, and its negative electrode is connected to the source of the first PMOS tube P1 and the source of the third PMOS tube P3; the negative electrode of the sixth diode D6 is connected to the other end of the reverse protection resistor Rbb, and its positive electrode is connected to the negative electrode of the fifth diode D5; the positive electrode of the fifth diode D5 is connected to the drain of the first PMOS tube P1 and the IN pin; the positive electrode of the second voltage regulator tube D2 is connected to the other end of the second resistor R2, the gate of the second PMOS tube P2 and the gate of the fourth PMOS tube P4, and its negative electrode is connected to the source of the second PMOS tube P2 and the source of the fourth PMOS tube P4; the negative electrode of the eighth diode D8 ... The positive electrode is connected to the negative electrode of the seventh diode D7; the positive electrode of the seventh diode D7 is connected to the drain of the second PMOS tube P2 and the IS pin; the drain of the third PMOS tube P3, the drain of the fourth PMOS tube P4, the positive electrode of the third diode D3, and the positive electrode of the fourth diode D4 are connected to a point; the negative electrode of the third diode D3 is connected to the drain of the first switch tube N1; the gate and source of the first switch tube N1 are connected to the gate of the power MOS tube; the negative electrode of the fourth diode D4 is connected to the drain of the second switch tube N2; the gate and source of the second switch tube N2 are connected to the gate of the fifth switch tube N5; the drain of the fifth switch tube N5 is connected to the gate of the sixth switch tube N6; the drain of the sixth switch tube N6 is connected to the gate of the power MOS tube; the source of the fifth switch tube N5 and the source of the sixth switch tube N6 are connected to the OUT pin; the two ends of the third resistor R3 are respectively connected to the source and gate of the fifth MOS tube. The first switch tube N1 and the second switch tube N2 are the same, both of which are depletion-type field effect tubes or JFET field effect tubes. The fifth switch tube N5 and the sixth switch tube N6 are the same, both of which are MOS tubes.

[0026] Principle of the invention:

[0027] When the power supply of the intelligent high-side switch chip is positively connected, the charge pump provides current to the GATE driving module. In order to turn on the power MOS tube in the GATE driving module, the current pull-down unit is turned off, the fifth switch tube N5 is turned on and the sixth switch tube N6 is turned off, the power MOS tube in the GATE driving module is turned on, and the charge pump provides current to the GATE driving module; when the power supply of the intelligent high-side switch chip is reversely connected, in the prior art, when the power supply is reversely connected, the charge pump does not work and the power MOS tube is cut off.

[0028] In the circuit of the present invention, when the power supply is reversely connected, the IN pin or the IS pin is used as the positive power supply, the reverse protection resistor Rbb and the diodes (D5 and D6, D7 and D8) form an internal reverse voltage source, the first switch tube N1 and the second switch tube N2 use a depletion field effect tube or a JFET field effect tube as a current source to provide voltage to the GATE drive module; the power MOS tube in the GATE drive module is cut off, and the reverse power protection circuit turns off the sixth switch tube N6 of the current pull-down unit. At this time, the reverse power supply generates a voltage drop Vbb1 on the reverse protection resistor Rbb, and then on the basis of this voltage drop Vbb1, the power MOS tube is controlled to be turned on through the first drive current generating unit and the second drive current generating unit connected in parallel.

[0029] If the IN pin is +5V, since the voltage drop of the first PMOS tube P1 itself is 0.7V, the corresponding voltage applied to the cathode of the first voltage regulator tube D1 is 4.3V. At this time, the voltage of the anode of the first voltage regulator tube is 3.6V (that is, the voltage drop of the fifth diode D5 minus the voltage drop of the sixth diode D6 minus the voltage drop of 0.7V at the IN pin 5V, and finally 3.6V). There is a 0.7V voltage drop (4.3V-3.6V) on the first voltage regulator tube D1, which makes the first PMOS tube P1 and the third PMOS tube P3 is turned on; further, the current of the first PMOS tube P1 and the third PMOS tube P3 flows through the fourth diode D4 and the second switch tube N2, so that the fifth switch tube N5 is turned on to turn off the sixth switch tube N6, thereby turning off the GATE pull-down current; at the same time, the current of the first PMOS tube P1 and the third PMOS tube P3 passes through the third diode D3 and the first switch tube N1 to pull up the GATE driving voltage, and the GATE driving voltage turns on the power MOS tube, thereby protecting the power MOS tube.

[0030] Similarly, if the IS pin is +5V, the voltage drop of the second PMOS tube P2 itself is 0.7V, and the corresponding voltage applied to the cathode of the second voltage regulator tube D2 is 4.3V. At this time, the voltage of the anode of the second voltage regulator tube is 3.6V, and there is a voltage drop of 0.7V on the second voltage regulator tube D2, which makes the second PMOS tube P2 and the fourth PMOS tube P4 turn on; further, the current of the second PMOS tube P2 and the fourth PMOS tube P4 flows through the fourth diode D4 and the second switch tube N2, so that the fifth switch tube N5 is turned on to turn off the sixth switch tube N6, thereby turning off the GATE pull-down current; at the same time, the current of the second PMOS tube P2 and the fourth PMOS tube P4 passes through the third diode D3 and the first switch tube N1, pulling up the GATE drive voltage, and the GATE drive voltage makes the power MOS tube turn on, which also plays a role in protecting the power MOS tube.

Claims

1. An intelligent high-side switch chip capable of realizing reverse power protection, comprising a VBB pin, an IN pin, an IS pin, an OUT pin, a charge pump, a GATE drive module and a reverse protection resistor Rbb; the drive module comprises a power MOS tube; the gate of the power MOS tube is connected to the output end of the charge pump, the source thereof is connected to the OUT pin, and the drain thereof is connected to the VBB pin and one end of the reverse protection resistor Rbb; the characteristics are as follows: It also includes a reverse power protection circuit; the reverse power protection circuit includes a first drive current generating unit, a second drive current generating unit, a current pull-up unit and a current pull-down unit; The current pull-up unit is used to pull up the driving voltage of the GATE driving module; The current pull-down unit is used to turn off the pull-down current of the GATE driving module; The first driving current generating unit includes a first resistor R1, a first voltage regulator tube D1, a sixth diode D6, a fifth diode D5, a first PMOS tube P1 and a third PMOS tube P3; The second driving current generating unit includes a second resistor R2, a second voltage regulator tube D2, an eighth diode D8, a seventh diode D7, a second PMOS tube P2 and a fourth PMOS tube P4; One end of the first resistor R1 and one end of the second resistor R2 are connected to the other end of the reverse protection resistor Rbb; the positive electrode of the first voltage regulator D1 is connected to the other end of the first resistor R1, the gate of the first PMOS transistor P1 and the gate of the third PMOS transistor P3, and the negative electrode thereof is connected to the source of the first PMOS transistor P1 and the source of the third PMOS transistor P3; the negative electrode of the sixth diode D6 is connected to the other end of the reverse protection resistor Rbb, and the positive electrode thereof is connected to the negative electrode of the fifth diode D5; the positive electrode of the fifth diode D5 is connected to the drain of the first PMOS transistor P1 and the IN pin; The anode of the second voltage regulator tube D2 is connected to the other end of the second resistor R2, the gate of the second PMOS tube P2 and the gate of the fourth PMOS tube P4, and the cathode thereof is connected to the source of the second PMOS tube P2 and the source of the fourth PMOS tube P4; the cathode of the eighth diode D8 is connected to the other end of the reverse protection resistor Rbb, and the anode thereof is connected to the cathode of the seventh diode D7; the anode of the seventh diode D7 is connected to the drain of the second PMOS tube P2 and the IS pin; The current pull-up unit includes a third diode D3 and a first switch tube N1; the current pull-down unit includes a fourth diode D4, a second switch tube N2, a third resistor R3, a fifth switch tube N5 and a sixth switch tube N6; the drain of the third PMOS tube P3, the drain of the fourth PMOS tube P4, the anode of the third diode D3 and the anode of the fourth diode D4 are connected as a point; the cathode of the third diode D3 is connected to the drain of the first switch tube N1; the gate and source of the first switch tube N1 are connected to the gate of the power MOS tube; the cathode of the fourth diode D4 is connected to the drain of the second switch tube N2; the gate and source of the second switch tube N2 are connected to the gate of the fifth switch tube N5; the drain of the fifth switch tube N5 is connected to the gate of the sixth switch tube N6 and the gate of the power MOS tube; the drain of the sixth switch tube N6 is connected to the gate of the power MOS tube; the source of the fifth switch tube N5 and the source of the sixth switch tube N6 are connected to the OUT pin; and the two ends of the third resistor are respectively connected to the source and gate of the fifth MOS tube.

2. The intelligent high-side switch chip capable of realizing reverse power protection according to claim 1, characterized in that: The first switch tube N1 and the second switch tube N2 are the same, both of which are depletion-type field effect tubes or JFET field effect tubes.

3. The intelligent high-side switch chip capable of realizing reverse power protection according to claim 1 or 2, characterized in that: The fifth switch tube N5 and the sixth switch tube N6 are the same, both of which are MOS tubes.

4. The intelligent high-side switch chip capable of realizing reverse power protection according to claim 3, characterized in that: The drain of the fifth switch tube N5 is connected to the gate of the power MOS tube through the fourth resistor R4.

5. The intelligent high-side switch chip capable of realizing reverse power protection according to claim 4, characterized in that: The drain of the sixth switch tube N6 is connected to the gate of the power MOS tube through the fifth resistor R5.

6. The protection method of the intelligent high-side switch chip capable of realizing reverse power supply protection according to any one of claims 1 to 5, characterized in that: When the power supply of the intelligent high-side switch chip is positively connected, the current pull-down unit is turned off, the power MOS tube in the GATE driver module is turned on, and the charge pump provides current to the GATE driver module; When the power supply of the intelligent high-side switch chip is reversely connected, the reverse protection resistor Rbb and the fifth diode D5 and the sixth diode D6, the seventh diode D7 and the eighth diode D8 form an internal reverse voltage source, and the first switch tube N1 and the second switch tube N2 act as current sources to provide voltage to the GATE drive module; the power MOS tube in the GATE drive module is cut off, and the sixth switch tube N6 of the current pull-down unit is turned off; the reverse power supply generates a voltage drop Vbb1 on the reverse protection resistor Rbb, and then on the basis of this voltage drop Vbb1, the power MOS tube is controlled to be turned on through the first drive current generating unit and the second drive current generating unit connected in parallel.

7. The protection method of the intelligent high-side switch chip capable of realizing reverse power supply protection according to claim 6, characterized in that: The control of turning on the power MOS tube specifically includes: If the IN pin is reversely connected to +5V, there is a voltage drop of 0.7V on the first voltage regulator D1, which turns on the first PMOS tube P1 and the third PMOS tube P3; the current of the first PMOS tube P1 and the third PMOS tube P3 flows through the fourth diode D4 and the second switch tube N2, so that the fifth switch tube N5 is turned on to turn off the sixth switch tube N6, thereby turning off the GATE pull-down current; at the same time, the current of the first PMOS tube P1 and the third PMOS tube P3 passes through the third diode D3 and the first switch tube N1, pulling up the GATE drive voltage, and the GATE drive voltage turns on the power MOS tube.

8. The protection method of the intelligent high-side switch chip capable of realizing reverse power supply protection according to claim 6, characterized in that: The control of turning on the power MOS tube specifically includes: If the IS pin is reversely connected to +5V, there is a voltage drop of 0.7V on the second voltage regulator tube D2, which turns on the second PMOS tube P2 and the fourth PMOS tube P4; the current of the second PMOS tube P2 and the fourth PMOS tube P4 flows through the fourth diode D4 and the second switch tube N2, so that the fifth switch tube N5 is turned on to turn off the sixth switch tube N6, thereby turning off the GATE pull-down current; at the same time, the current of the second PMOS tube P2 and the fourth PMOS tube P4 passes through the third diode D3 and the first switch tube N1, pulling up the GATE drive voltage, and the GATE drive voltage turns on the power MOS tube.

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