Si9161

The Si9161 Optimized-Efficiency Controller for RF Power Amplifier Boost Converter is a fixed-frequency, pulse- widthmodulated power conversion controller designed for use with the Si6801 application specific MOSFET. The Si9161 and the Si6801 are optimized for high efficiency switched-mode power conversion at 1 MHz and over. The device has an enable pin which can be used to put the converter in a low-current mode compatible with the standby mode of most cellular phones. It has a light-load pin which enables circuitry optimizing efficiency at loads typical of receive operation. A wide bandwidth feedback amplifier minimizes transient response time allowing the device to meet the instantaneous current demands of today's digital protocols. The input voltage range accommodates minimal size and cost battery pack configurations.

Frequency control in switching is important to noise management techniques in RF communications. The Si9161 is easily synchronized for high efficiency power conversion at frequencies in excess of 1 MHz.

Optimizing the controller and the synchronous FETs results in the highest conversion efficiency over a wide load range at the switching frequencies of interest (1 MHz or greater). It also minimizes the overshoot and gate ringing associated with drive current and gate charge mismatches.

When disabled, the converter requires less than 330 A. This capability minimizes the impact of the converter on battery life when the phone is in the standby mode.

Finally, operating voltage is optimized for LiIon battery operation (2.7 V to 4.5 V) and can also be used with three-cell NiCd or NiMH (3 V to 3.6 V), as well as four-cell NiCd or NiMH (4 V to 4.8 V) battery packs.