DRV10975_15 Datasheet, PDF (11/57 Pages) Texas Instruments – DRV10975 12-V, Three-Phase, Sensorless BLDC Motor Driver

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DRV10975
SLVSCP2 – JANUARY 2015
9.3 Feature Description
9.3.1 Regulators
9.3.1.1 Step-Down Regulator
The DRV10975 includes a step-down voltage regulator that can be operated as either a switching buck style
regulator or as a linear regulator (see Figure 3). The regulator output voltage can be configured by register bit
VregSel. When VregSel = 0, the regulator output voltage is 5 V, and when VregSel = 1, the regulator output
voltage is 3.3 V.
If the step-down regulator is configured as buck style, refer to I_{REG_MAX} in the Electrical Characteristics to
determine the amount of current provided for external load. If the step-down regulator is configured as linear
mode, it is used for the device internal circuit only.
IC
3.3 V/5 V
VREG
VCC
SW
47 µH
10 µF
IC
Load
3.3 V/5 V
VREG
VCC
SW
39 Ω
10 µF
SWGND
SWGND
Buck Regulator
Linear Regulator
Figure 3. Step-Down Regulator Configurations
9.3.1.2 3.3-V and 1.8-V LDO
The DRV10975 includes a 3.3-V LDO and an 1.8-V LDO. The 1.8-V LDO is for internal circuit only. The 3.3-V
LDO is mainly for internal circuits, but can also drive external loads not to exceed I_{V3P3_MAX} listed in the Electrical
Characteristics. For example, it can work as a pullup voltage for the FG, DIR, SDA, and SCL interface.
Both V1P8 and V3P3 capacitor must be connected to GND.
9.3.2 Protection Circuits
9.3.2.1 Thermal Shutdown
The DRV10975 has a built-in thermal shutdown function, which shuts down the device when junction
temperature is more than T_SDN ˚C and recovers operating conditions when junction temperature falls to T_SDN –
T_{SDN_HYS}˚C.
The OverTemp status bit (address 0x10 bit 7) is set during thermal shutdown.
9.3.2.2 UVLO
The DRV10975 has a built-in UVLO function block. The hysteresis of UVLO threshold is V_UVLO-HYS. The device is
locked out when VCC is down to V_{UVLO_F} and woke up at V_{UVLO_R}.
9.3.2.3 Current Protection
The overcurrent shutdown function acts to protect the device if the current, as measured from the FETs, exceeds
the I_OC-limit threshold. It protects the device in the short-circuit condition if by accident phase shorts to GND, or
phase shorts to phase; the DRV10975 places the output drivers into a high-impedance state and maintains this
condition until the overcurrent is no longer present. The OverCurr status bit (address 0x10 bit 5) is set.
The DRV10975 also provides acceleration current limit and lock detection current limit functions to protect the
device and motor (see Current Limit and Lock Detect and Fault Handling).
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