SH3100 Datasheet, PDF (12/80 Pages) Semtech Corporation – Supervisory IC with I2C Interface and PWM

SH3100
POWER MANAGEMENT
Operating Modes (continued)
Mode
7
8
9
LDO
NO
NO
NO
Switching Fan
Reset
Regulator Control Duration
Notes
Normal boost regulation from VDD to VBAK with external
YES
NO
NO
switching FET and transfer diode. Operation is as mode six
but regulator feedback is determined by the internal VBAK
divider
Buck regulation from VDD to a separate supply with external
switching FET and transfer diode. Regulator feedback is input
YES
NO
NO
on the SNSE pin. The PWM pin drives an external PMOS
or PNP switching the inductor to VDD and is Low during the
inductor energize period and High during the transfer period
(to allow current to flow through the external diode)
Buck regulation from VDD to VBAK with external switching
YES
NO
NO FET and transfer diode. Operation is as mode 8 but regulator
feedback is determined by the internal VBAK divider
© 2006 Semtech Corp.
12
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