DRV8808 Datasheet, PDF (20/38 Pages) Texas Instruments – COMBINATION MOTOR DRIVER WITH DC-DC CONVERTER

DRV8808
SLVS857A – DECEMBER 2009 – REVISED AUGUST 2011
Charge
Pump
A_CONT
(Regulator A Only)
VM
Overcurrent
Sense
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Control Logic
and
Vref
Predriver
1V
OD_x
Output
Voltage
Supervisor
Disable
(Mask)
UVP OVP
(–30%) (+30%)
C_SELECT
Current Limit
Overcurrent Protect
Detect Disable
Soft Start,
Protection Control,
and
nORT Assertion
FBx
External catch diode
Vf < 1.2 V at peak current,
(1.25 ´ Iout) assuming
330-µH inductor
Setup/Extended Setup
Register
Figure 8. DC-DC Converter
This is a switch-mode regulator with integrated switches, to provide a programmed output set by the feedback
terminal. The dc-dc converter has a variable duty cycle topology. External filtering (inductor and capacitor) and
external catch diode are required. The output voltage is short circuit protected.
The regulator has a soft-start function to limit the rush current during start-up. It is achieved by using VFB ramp
during soft start.
For unused dc-dc converter channels, the external components can be removed if the channel is set to inactive
by the CSELECT pin and register bits. Recommend connecting unused FB pin to GND or V3p3 (pin 17).
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