Date: 19/03/2009

12V hot swap controller with integrated hall-effect sensor

Allegro launched a new 12 V hot swap controller with power good indication. The ACS761 is an integrated Hall-effect current sensor with an integrated charge pump, gate driver, and multiple levels of load fault protection. Hot swap control and short circuit protection are provided in a single IC without the need for an external shunt resistor.

Some of the features are:

1. The resistance of the ACS761 internal current conductor is typically 1.5 mO, resulting in power savings relative to shunt resistor based hot swap solutions without a reduction in sensing accuracy.
2. It also provides a 240VA protection.
3. Fixed Over Current Fault Threshold - Set internally to 40 A
4. It has PGOOD pins - Provides feedback to host system that the 12 V supply is enabled and eliminates external system logic components.
5. ACS761 also integrates an FET driver.
6. It is targeted at the computer/office automation market, most specifically for server applications.

The integrated protection in the ACS761 incorporates three levels of fault protection, which includes a Power Fault with user-selectable delay, an Overcurrent Fault threshold with user selectable delay, and Short Circuit protection, which disables the gate of an external pass FET in less than 2 µs. These faults are indicated to the host system via the Fault pin and are cleared upon reasserting the chip enable pin to the high state.

Further information about Allegro can be found at www.allegromicro.com