Diodes Introduced Single-Chip Fan Driver

Published:2011/9/23 3:17:00 Author:Amy From:SeekIC

Diodes, a leading global manufacturer and supplier of high-quality application specific standard products, has introduced the industry’s smallest fully featured single-chip fan driver with high-output drive capability to provide a cost-effective solution for fan and motor drive applications. These devices are developed for driving low-power single-phase brushless DC (BLDC) fans and motors. The AH5795 can offer an motor current up to 500mA. Using Diodes’ low-profile DFN packaging technology, the AH5795 integrates a high-sensitivity Hall effect sensor, amplifier and an internal H-bridge driver output stage. A PWM speed control pin provides improved motor speed control through changing the duty ratio of the PWM signal as well as supply voltage.

Its voltage range is 1.8V to 6V which meets the requirement of low operating voltage BLDC fans. In addition, the AH5795’s bi-directional full-bridge driver adopts soft switching to lower audible switching noise and electromagnetic interference (EMI).

The motor controller has integrated locked rotor detection and automatic self-restart functions, which used to shutdown the output driver in the event of a locked rotor and then restart the motor when the rotor is freed. Additionally, a tachometer output is provided by an open-drain frequency generator, which enables external speed monitoring. The all-in-one smart motor controller eliminates the need for most of the external components, including a timing capacitor.


The operating temperature range of AH5795 is -40°C to 105°C, and it is ideal for thermally demanding applications like enclosed space in fan motors.

An additional member of the smart fan motor controller family will be launched later this year, which includes all of the features and functionality of the AH5795 plus internal timing advance to improve tail-end current, thus enabling further reduction of audible and EMI noise.

The device is available in low-profile DFN2020-6 and TSOT23-6 packages. The price is $US0.30 in quantities of 1k.

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