AIC1570

The AIC1570 combines a synchronous voltage mode controller with a low dropout linear regulator and a linear controller as well as the monitoring and protection functions in this chip. The PWM controller regulates the microprocessor core voltage with a synchronous rectified buck converter. The linear controller regulates power for the GTL bus and the linear regulator provides power for the clock driver circuit.

An integrated 5 bit D/A converter that adjusts the core PWM output voltage from 2.1V to 3.5V in 0.1V increments and from 1.3V to 2.05V in 0.05V increments. The linear regulator of AIC1570 uses an internal driver device to provide 2.5V2.5%. The linear controller drives with an external N-channel MOSEFET to provide 1.5V2.5%.

This AIC1570 chip monitors all the output voltages. Power Good signal of AIC1570 is issued when the core voltage is within 10% of the DAC setting and the other levels are above their under-voltage levels. Over-voltage protection for the core output uses the lower N-channel MOSFET to prevent output voltage above 115% of the DAC setting. The PWM over-current function monitors the output current by using the voltage drop across the upper MOSFETs RDS(ON), eliminating the need for a current sensing resistor.