Fan motor power failure automatic brake circuit

Abstract

The invention provides a fan motor power failure automatic brake circuit which comprises an energy storage unit, a motor driving circuit, a control unit and a resistance unit connected with an input power source. The energy storage unit is electrically connected with the motor driving circuit and used for receiving and storing an operation voltage. The motor driving circuit is provided with multiple upper and lower arm switch assemblies, a first driving unit and a second driving unit. The control unit is electrically connected with a third end opposite to the lower arm switch assemblies and a second end opposite to the first and second driving units. The operation voltage is provided for the upper arm switch assemblies through the energy storage unit for conduction, and therefore the upper arm switch assemblies and a motor coil form a closed loop to achieve brake.

Description

[0001] 【Technical field】 [0002] The invention relates to a circuit for automatic braking of a fan motor when power is off, especially to a circuit for automatic braking of a fan motor with an automatic braking function. [0003] 【Background technique】 [0004] In recent years, the use of a digital microcontroller (Micro-Controller Unit, MCU) combined with a power electronic switch drive circuit to design electronic products has become a commonly used technology in the industry. However, when operating the electronic product, the digital microcontroller and the power electronic switch will cause the electronic product to generate a lot of heat due to high frequency operation; therefore, the heat dissipation requirement of the electronic product will become a very important design issue. [0005] At present, the more common heat dissipation method uses the operation of the fan system to drive the wind and heat dissipation of the electronic product. However, based on the conside...

AI Technical Summary

Problems solved by technology

However, since it is known that the fan brake circuit 1 needs the controller 13 to perform pulse width modulation signal (PULSE WIDTH MODULATION; PWM) cutting control on the two lower arm switches M3 and M4, the controller 13 is changed to the second upper arm switch M1. , M2 to do pulse width modulation signal cutting control, but the temperature of the two upper arm switches M1, M2 and the control resistor will rise, so it is necessary to add electronic components (such as resistors) to solve the above temperature rise problem, and two times The arm switches M3 and M4 are electrically connected to the brake circuit 14, which will inevitably increase the cost and increase the complexity of the circuit connection due to the setting of the brake circuit 14.

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