A power supply voltage detection circuit and undervoltage protection power supply chip

Abstract

The invention provides a power supply voltage detection circuit and an undervoltage protection power supply chip, through the setting of the first voltage detection circuit, power supply voltage selection circuit, second voltage detection circuit, and control output circuit, without changing any parameters, effective Compatible with two operating voltage systems, the products made by using the circuit and chip of the present invention can realize that when the battery of the first operating voltage is used as the power supply, when the power supply voltage is lower than the shutdown setting threshold of the first voltage range, the system Stop working and protect the battery. When the power supply voltage returns to the startup setting threshold of the first voltage range, the system starts to work; similarly, for the second working voltage as the power supply, when the power supply voltage is lower than the shutdown setting threshold of the second voltage range When the threshold is set, the system stops working to protect the battery. When the power supply voltage returns to the start-up threshold of the second voltage range, the system starts to work normally.

Description

technical field [0001] The invention relates to the field of switching power supplies, in particular to a power supply voltage detection circuit and an undervoltage protection power supply chip. Background technique [0002] Electronic devices in different application environments usually have different working voltages. For example, the power supply voltage of cars and trucks is usually different. The voltage of cars is 12V, the voltage of trucks is 24V, and the corresponding cars are equipped with 12V batteries (with The voltage range of the car battery is 10V-13.8V), and the truck is equipped with a 24V battery (the voltage range of the truck battery is 20V- 27.6V), the corresponding operating voltages of the car and truck on-board electronic equipment are nominally 12V and 24V. [0003] When the engine stops working, only the battery supplies power to the electronic equipment. If the equipment works for a long time, the battery power may be exhausted, and the battery wi...

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Problems solved by technology

[0003] When the engine stops working, only the battery supplies power to the electronic equipment. If the equipment works for a long time, the battery power may be exhausted, and the battery will be completely consumed due to power consumption, which will cause battery damage. To solve this problem, usually by setting the power The undervoltage protection point of the chip is used to set the minimum working voltage of the on-board electronic equipment to protect the battery. However, different battery voltages require different parameters to be set, which makes the same parameter incompatible with devices with different working voltages. production troubles

[0004] For the on-board electronic equipment of cars and trucks, the current solution is basically to use different voltage divider resistors and set different undervoltage protection points. The problem is that the materials of the products cannot be used in common. When two products are produced at the same time, it is easy to mix materials. , increasing the difficulty of production control

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