Table 1-1 highlights the latest POL DC/DC converters with integrated MOSFETs and controllers suitable for Alder Lake applications. The suggested devices are selected to accommodate different input voltage and control mode requirements over a wide range of output current. The featured devices in the left column accommodate a maximum input voltage of 22 V or greater, and are designed to achieve fast load-transient response with an adaptive on-time control mode, high light and full-load efficiency, and low quiescent current.

Several devices include an integrated programmable voltage identification (VID) supporting the processor's adaptive voltage requirements. The alternate devices in the right column employ fixed-frequency current-mode control with frequency synchronization useful in noise-sensitive industrial applications, and operate up to a 17 V input. If VID is required with alternative devices, consider the LM10011 VID voltage programmer in addition to the converter's resistor divider network.

The POL regulators generating low voltages from an array of batteries must employ an energy-saving pulse-skipping technique now referred to as Eco-Mode. The inductor current in a synchronous-buck converter is a triangle wave. As the output current decreases from a heavy-load condition, the inductor current is reduced and the rippled valley of the triangle wave eventually touches the zero level at the boundary between continuous conduction-mode (CCM) and discontinuous conduction node (DCM).

With Eco-Mode, the rectifying MOSFET is turned off when the converter detects zero current in the inductor. As the load current further decreases, the on-time is held nearly constant so that the off-time is extended, and the switching frequency is reduced to maintain regulation. As a result, the power MOSFETs and inductor are idle for longer time periods and conduction losses are greatly reduced. DC/DC converters and controllers with low quiescent current will have improved light-load efficiency performance and extended battery run-time, since less power is dissipated within the IC. The TPS51825A features Ultra Low Quiescent current (ULQ) of 25-uA for longer battery life in system stand-by mode.

Figure 2-1 shows 90% efficiency with 7.4-V input and 5-V output at 1-mA, illustrating the combined affects of Eco-Mode and ULQ.

Figure 2-1 TPS51285A Efficiency Plot

The TPS51215A supports a 2-bit VID and Low Power Mode(LPM) to dynamically change the output voltage to satisfy Intel IMVP8/9 applications for VCCIN_AUX, VCCIO_0, and VCCIO_1_2 rails. A fixed 0V output voltage and up to three voltage levels can be programmed externally with a voltage divider circuit. The device can also be configured to provide a 1-bit VID output voltage. Please see the TPS51215A Single Phase, D-CAP2^TM Controller with 2-Bit VID Control and Low Power Mode data sheet for more information.