Ultra-low RDS switch control circuit

Abstract

The utility model provides an ultra-low RDS switch control circuit, the ultra-low RDS switch control circuit comprises a switch control chip, the switch control chip comprises a voltage input pin IN, a switch control pin EN, a voltage output pin OUT, a current limiting pin ISET and a chip ground GND, the voltage input pin IN is grounded through an input capacitor C1, the voltage output pin OUT is grounded through an output capacitor C2, and the current limiting pin ISET is grounded through a chip ground GND. The chip ground GND is grounded, and the current limiting pin ISET is grounded through a resistor R. The programmable current limiting circuit has a programmable current limiting function, and a user can set a proper current limiting value according to an actual application scene, so that a power supply is effectively protected from being damaged by overcurrent and short circuit.

Description

TECHNICAL FIELD

[0001] The utility model relates to switch technical field especially relates to a kind of ultra-low RDS switch control circuit. BACKGROUND

[0002] In the field of power management, the performance of switch is directly related to the stability and safety of equipment, since switch is widely used in various electronic devices, how to ensure that switch can provide stable and reliable power output, protect the normal operation of equipment is very necessary.

[0003] In order to effectively protect the power supply from the damage of overcurrent and short circuit, how to set appropriate current limit value according to actual application scene, so that the switch has programmable current limit function, is a problem to be solved. UTILITY MODEL CONTENTS

[0004] The technical problem to be solved by the utility model is how to set appropriate current limit value according to actual application scene, so that the switch has programmable current limit function, so that the power supply is protected from the damage of overcurrent and short circuit, and an ultra-low RDS switch control circuit is provided.

[0005] The technical scheme adopted by the utility model to solve the above technical problem is as follows:

[0006] An ultra-low RDS switch control circuit is provided, which comprises a switch control chip, the switch control chip comprises a voltage input pin IN, a switch control pin EN, a voltage output pin OUT, a current limiting pin ISET and a chip ground GND, the voltage input pin IN is grounded through an input capacitor C1, the voltage output pin OUT is grounded through an output capacitor C2, the chip ground GND is grounded, the current limiting pin ISET is grounded through a resistor Rset, wherein the switch control chip is integrated with a conducting MOSFET and a gate driver, the gate of the conducting MOSFET is connected with the gate driver, the gate driver is connected with the switch control pin EN, the drain of the conducting MOSFET is connected with the voltage input pin IN, the source of the conducting MOSFET is connected with the voltage output pin OUT, and two parasitic body diodes are sequentially arranged between the drain and the source of the conducting MOSFET.

[0007] Further, the ISET pin is connected with the resistor Rset to ground, and the current can be limited, and the current limiting formula is as follows: ILIM(A)=6800 / RSET(Ω).

[0008] Further, the switch control chip is further integrated with a resistor, an output discharge control module and a current limiting module, one end of the resistor is connected to a wire between the on-MOSFET source and the voltage output pin OUT, the other end of the resistor is connected to the current limiting module, the output discharge control module is connected to the voltage output pin OUT, and the current limiting module is arranged between the gate driver and the current limiting pin ISET.

[0009] Further, the resistor is a current sensing resistor or a sampling resistor.

[0010] Further, the switch control chip is further integrated with an under-voltage protection module, one end of the under-voltage protection module is connected to a wire between the on-MOSFET drain and the voltage input pin IN, and the other end of the under-voltage protection module is connected to the gate driver.

[0011] Further, the switch control chip is further integrated with a temperature detection module connected to the gate driver.

[0012] Compared with the prior art, the ultra-low RDS switch control circuit comprises a switch control chip, the switch control chip comprises a voltage input pin IN, a switch control pin EN, a voltage output pin OUT, a current limiting pin ISET and a chip ground GND, the voltage input pin IN is grounded through an input capacitor C1, the voltage output pin OUT is grounded through an output capacitor C2, the chip ground GND is grounded, and the current limiting pin ISET is grounded through a resistor R, which has a programmable current limiting function, and a user can set a suitable current limiting value according to an actual application scene, so that the power supply is effectively protected from damage caused by overcurrent and short circuit, in addition, the switch control chip also has a reverse blocking function, which effectively eliminates the problems that may be caused by a body diode, this function enables the switch chip to maintain stable performance under a reverse voltage, and improves the reliability of the equipment. In addition, when the switch is in a shutdown state, VOUT can be forced to be higher than VIN, which provides a larger voltage regulation range for the equipment and prevents reverse flow of current from the output to the input. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description, and obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in the drawings without creative labor.

[0014] Figure 1is a schematic view of an ultra-low RDS switch control circuit provided by the embodiment.

[0015] Figure 2 is a packaging structure diagram of a switch control chip of an ultra-low RDS switch control circuit provided by the embodiment. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and do not limit the utility model.

[0017] The implementation of the utility model will be described in detail below in combination with specific embodiments.

[0018] As shown in Figure 1 and Figure 2 In the embodiment of the utility model, an ultra-low RDS switch control circuit is provided, which comprises a switch control chip, the switch control chip comprises a voltage input pin IN, a switch control pin EN, a voltage output pin OUT, a current limiting pin ISET and a chip ground GND, the voltage input pin IN is grounded through an input capacitor C1, the voltage output pin OUT is grounded through an output capacitor C2, the chip ground GND is grounded, the current limiting pin ISET is grounded through a resistor Rset, the ISET pin is externally connected to the ground through the resistor Rset, and the current can be limited, through this function, the user can set a suitable current limiting value according to the actual application scene, thereby effectively protecting the power supply from damage caused by overcurrent and short circuit.

[0019] In the embodiment, the switch control chip is integrated with a conducting MOSFET and a gate driver, the gate of the conducting MOSFET is connected with the gate driver, the gate driver is connected with the switch control pin EN, the drain of the conducting MOSFET is connected with the voltage input pin IN, the source of the conducting MOSFET is connected with the voltage output pin OUT, the gate driver charges and discharges the gate of the MOSFET in a control mode, thereby controlling the rising time of the device, two parasitic diodes are sequentially arranged between the drain and the source of the conducting MOSFET, the conducting MOSFET is the main element of the switch chip, which determines the maximum input voltage and the maximum load current that the switch chip can handle, the on-resistance of the switch chip is the characteristic of the conducting MOSFET, which is used to calculate the power consumption of the switch chip, the ultra-low RDS means that the current loss of the conducting MOSFET is small in the on state, thereby reducing the power consumption and heat loss, so that the switch control chip also has a reverse blocking function, which effectively eliminates the problems that may be caused by the body diode, this function enables the switch chip to maintain stable performance under reverse voltage, thereby improving the reliability of the device. In addition, when the switch is in the shutdown state, VOUT can be forced to be higher than VIN, which provides a larger voltage regulation range for the device and prevents reverse flow of current from the output to the input.

[0020] In the embodiment, the ISET pin is connected with the resistor Rset to the ground, the current can be limited, and the current limiting formula is as follows: ILIM(A) = 6800 / RSET(Ω), in simple terms, the working current of the input voltage of the voltage input pin IN is controlled, for example, the external resistance Rset is 6.8K, and the current is 1A, when the current of the external load exceeds 1A, the switch control chip is turned off, and the load cannot work directly.

[0021] In the embodiment, the switch control chip is also integrated with a resistor, an output discharge control module and a current limiting module, here, when the current passes through the resistor (which is a current sensing resistor or a sampling resistor), a voltage drop is generated. By measuring this voltage drop, the size of the current passing through the circuit can be indirectly calculated, one end of the resistor is connected to the wire between the source of the conducting MOSFET and the voltage output pin OUT, the other end of the resistor is connected with the current limiting module, the output discharge control module is connected with the voltage output pin OUT, in this way, when the switch control pin EN disables the device, the output discharge control module is turned on, which will discharge the output node, thereby preventing the output from floating, the current limiting module is arranged between the gate driver and the current limiting pin ISET, which can limit the current.

[0022] It should be noted that in the embodiment, the output discharge control module is a sheet-shaped resistor.

[0023] In the embodiment, an under-voltage protection module is also integrated in the switch control chip, one end of the under-voltage protection module is connected to a wire between the conducting MOSFET drain and the voltage input pin IN, and the other end of the under-voltage protection module is connected to the gate driver, so that when the input voltage exceeds a set value, the switch chip automatically cuts off the power supply, thereby protecting the back-end circuit from high-voltage impact. This function is particularly important in practical applications, and can effectively avoid equipment damage or safety accidents caused by excessively high voltage.

[0024] In the embodiment, a temperature detection module connected to the gate driver is also integrated in the switch control chip, so that when the internal temperature of the switch chip is too high, it will automatically reduce the current or shut down the switch chip to prevent safety hazards caused by overheating.

[0025] Compared with the prior art, the ultra-low RDS switch control circuit provided by the utility model, which comprises a switch control chip, the switch control chip comprises a voltage input pin IN, a switch control pin EN, a voltage output pin OUT, a current limiting pin ISET and a chip ground GND, the voltage input pin IN is grounded through an input capacitor C1, the voltage output pin OUT is grounded through an output capacitor C2, the chip ground GND is grounded, the current limiting pin ISET is grounded through a resistor R, and the switch control chip has a programmable current limiting function, a user can set a suitable current limiting value according to the actual application scene, thereby effectively protecting the power supply from overcurrent and short circuit damage, in addition, the switch control chip also has a reverse blocking function, effectively eliminating the problems that may be caused by no body diode, the function enables the switch chip to maintain stable performance under reverse voltage, and the reliability of the equipment is improved. In addition, when the switch is in a shutdown state, VOUT can be forced to be higher than VIN, thereby providing a larger voltage regulation range for the equipment, and preventing reverse flow of current from the output to the input.

[0026] The above only describes the preferred embodiments of the utility model, and does not limit the utility model, and any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. An ultra-low RDS switch control circuit, characterized by, The switch control chip comprises a voltage input pin IN, a switch control pin EN, a voltage output pin OUT, a current limiting pin ISET and a chip ground GND, the voltage input pin IN is grounded through an input capacitor C1, the voltage output pin OUT is grounded through an output capacitor C2, the chip ground GND is grounded, and the current limiting pin ISET is grounded through a resistor Rset, wherein a conducting MOSFET and a gate driver are integrated in the switch control chip, the gate of the conducting MOSFET is connected with the gate driver, the gate driver is connected with the switch control pin EN, the drain of the conducting MOSFET is connected with the voltage input pin IN, the source of the conducting MOSFET is connected with the voltage output pin OUT, and two parasitic body diodes are arranged in sequence between the drain and the source of the conducting MOSFET.

2. An ultra-low RDS switch control circuit as defined in claim 1, wherein, The ISET pin is connected with the resistor Rset to the ground, and the current can be limited, and the current limiting formula is as follows: ILIM(A) = 6800 / RSET(Ω).

3. An ultra-low RDS switch control circuit as defined in claim 1, wherein, The switch control chip further comprises a resistor, an output discharge control module and a current limiting module, one end of the resistor is connected to a wire between the source of the conducting MOSFET and the voltage output pin OUT, the other end of the resistor is connected with the current limiting module, the output discharge control module is connected with the voltage output pin OUT, and the current limiting module is arranged between the gate driver and the current limiting pin ISET.

4. An ultra-low RDS on switch control circuit as defined in claim 3, wherein, The resistor is a current sensing resistor or a sampling resistor.

5. An ultra-low RDS switch control circuit as defined in claim 1, wherein, The switch control chip further comprises an under-voltage protection module, one end of the under-voltage protection module is connected to a wire between the drain of the conducting MOSFET and the voltage input pin IN, and the other end of the under-voltage protection module is connected with the gate driver.

6. An ultra-low RDS switch control circuit as defined in claim 1, wherein, The switch control chip further comprises a temperature detection module connected with the gate driver.

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