SH3100IMTR SEMTECH [Semtech Corporation], SH3100IMTR Datasheet - Page 14

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SH3100IMTR

Manufacturer Part Number
SH3100IMTR
Description
Supervisory IC with I2C Interface and PWM
Manufacturer
SEMTECH [Semtech Corporation]
Datasheet
© 2006 Semtech Corp.
POWER MANAGEMENT
Application Diagrams - Modes 4 to 6
Mode 4 – Bootstrap boost regulation using
internal switching FET
VDD is stepped up from external supply source
using internal switching on PWM.
Starts up with external supply as low as 1.8 V and
continue to operate as external supply drops as low
as 1 V.
Regulation timing for all switching regulator modes
is set by internal programmable HFDCO oscillator.
Register settings
Mode 5 – Bootstrap boost regulation using
external switching FET.
VDD is stepped up from external supply source
using external switching FET controlled by PWM.
Use for higher load requirements.
Regulated output voltage is set by internal DAC8.
Feedback is fixed as VDD/3.
1Mohm pull-down resistor is required to indicate
external switching configuration to SH3100.
Register settings
Mode 6 – Normal boost regulation using external
FET & external feedback divider
Regulated supply is stepped up from VDD using
external switching FET controlled by PWM.
Regulated output voltage is set by internal DAC8
and feedback on SNSE.
1Mohm resistor indicates external switching and
also ensures NMOS is turned off during power up
Register settings
DeviceMode = 001
ComparatorSource = 00 (VDD)
CLK1HF/LF = 1
ForcedDACValue = xx (to set VDD level)
Set CLK1 frequency as desired
DeviceMode = 001
ComparatorSource = 00 (VDD)
CLK1HF/LF = 1
ForcedDACValue = xx (to set VDD level)
Set CLK1 frequency as desired
DeviceMode = 001
ComparatorSource = 11 (SNSE)
CLK1HF/LF = 1
ForcedDACValue = xx (to set VDD level)
Set CLK1 frequency as desired
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SH3100

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