The LTC1699, a precision 2-state resistive divider that uses a simple SMBus interface to allow VID control on non-VID-enabled DC/DC converters, is described.
2-state resistive divider
Many modern CPUs run at two different clock speeds, where each speed requires a different core operating voltage to assure optimum performance. These voltages are documented in the manufacturer’s VID (voltage identification) section of the CPU specification. Some new DC/DC converters (the LTC1909, for example) have built-in VID control that supports dual programmable output voltages, but many existing ...