Alpha and Omega’s AOZ9007 Battery Protection IC

Posted by  21 April 2010

Chipworks recently extracted and analyzed the circuits from Alpha and Omega’s AOZ9007 battery protection IC. This chip is used for lithium-ion rechargeable battery packs, and competes with products from Sony, Texas Instruments, Fairchild Semiconductor, ON Semiconductor, Analog Devices, and Maxim Semiconductor.

When it first landed on my desk, I figured that it was “just another IC with comparator circuits” – ho hum.

However, once the analysis progressed I found some surprising things.

The AOZ9007 battery protection IC consists of a two-stacked die. The battery protection package includes a power control integrated circuit stacked on top of an integrated dual common drain MOSFET. With this configuration, not only will the battery protection IC have better performance, it will also be smaller. Effectively reducing the area of this device, making it suitable for power controllers where size is an issue.

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Figure 1: Alpha and Omega AOZ9007 battery protection IC x-ray and die photos
Also, this is not just “another IC with comparator circuits.” These comparators act as detectors that prevent the single cell lithium-ion rechargeable battery packs from overcharge, over discharge, and over-current conditions. Hence, they are sensors that will put more life into your battery.

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Figure 2: Detector circuits (circled) for the battery protection IC
The power control IC consists of a number of constant-current logic gates such as inverters. This is in contrast to “normal” inverters with the PMOS and NMOS source connected directly to VDD and GND. These constant-current inverters are used not only in the oscillator but everywhere that constant-current is required.

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Figure 3: Logic circuit showing the constant-current gates
We extracted the full device, including the oscillator, counter, logic circuits 1 and 2, short-circuit detector, etc. Clients in this market will find the Alpha and Omega AOZ9007 battery protection IC to be a very compelling industry benchmark.

Last modified on Wednesday, 21 April 2010 10:46