DRV8808 Datasheet, PDF (19/38 Pages) Texas Instruments – COMBINATION MOTOR DRIVER WITH DC-DC CONVERTER

DRV8808
www.ti.com
SLVS857A – DECEMBER 2009 – REVISED AUGUST 2011
Charge Pump
The charge-pump voltage generator circuit utilizes, external storage, and bucket capacitors. It provides the
necessary voltage to drive the high-side switches, for both dc-dc regulators and motor driver. The charge-pump
circuit is driven at a frequency of 1.6 MHz (nom). Recommended bucket capacitance (connected from CP1 to
CP2) is 10 nF, rated at 55 V (minimum), and storage capacitance is 0.1 μF, at 16 V (minimum). The
charge-pump storage capacitor, Cstorage, should be connected from the CP output to V_M.
For power save in sleep mode, the charge pump is stopped when N_SLEEP = L and all three regulators are
turned OFF. When the part is powered up, the charge pump is started first after the CSELECT capture and, 10
ms later from the CP startup, the first regulator is started up.
Table 8. Charge Pump ^{(1) (2)}
FAULT CONDITION
X
X
X
X
0
Motor OCP
TSD
DC-DC Ch-A
OFF
ON
X
X
X
X
OFF
DC-DC Ch-B
OFF
X
ON
X
X
X
OFF
DC-DC Ch-C
OFF
X
X
ON
X
X
OFF
nSleep
0
X
X
X
1
1
X
CHARGE PUMP
OFF
ON
ON
ON
ON
ON
OFF
(1) X = Don't care
(2) DC=DC status in fault condition is determined by serial register settings, TSD Control table, and MISD Control table. These tables define
status of charge pump.
Copyright © 2009–2011, Texas Instruments Incorporated
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