LTC3734 Datasheet, PDF (25/28 Pages) Linear Technology – Single-Phase, High Efficiency DC/DC Controller for Intel Mobile CPUs

LTC3734
TYPICAL APPLICATIO
Figure 9 shows a typical application using the LTC3734 to
power the mobile CPU core. The input can vary from 5V to
24V; the output voltage can be programmed from 0.7V to
1.708V with a maximum current of 20A. By only modifying
the external MOSFET and inductor selection, higher load
current capability can be achieved.
The power supply in Figure 9 receives a VRON signal for
ON/OFF control. After soft-start, the output voltage is set
at 1.2V until the assertion of the MCH_PG signal. After
about a 50μs delay, the VID5-VID0 bits gain the control
over the output voltage and program it between 0.7V and
1.708V. When the STP_CPUB signal is low, a deep sleep
state is indicated and the output voltage is decreased by
about 1.04%. When the DPRSLPVR signal is high, a
deeper sleep state is indicated and the output voltage
becomes 0.748V regardless of the states of the VID bits.
Active voltage positioning is accomplished with a resistive
divider across the I_TH pin. Lower resistance yields a
steeper AVP slope while higher resistance provides a
flatter slope. Finally, the PGOOD output is masked for
110μs during VID change or state transition.
3734f
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