MP6515 – 35V, 2.8A, PHASE/ENABLE CONTROL, H-BRIDGE MOTOR DRIVER
MP6515 Rev. 1.02 www.MonolithicPower.com 11
9/18/2017 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2017 MPS. All Rights Reserved.
Blanking Time
There is often a current spike during the turn-on,
due to the body diode’s reverse-recovery
current or the shunt capacitance of the load.
This current spike requires filtering to prevent it
from erroneously shutting down the high-side
MOSFET. An internal fixed blanking time (t
OCPD
)
blanks the output of the current sense
comparator when the outputs are switched.
This blanking time also sets the minimum on
time for the high-side MOSFET.
Input Logic
For the MP6515, control of the outputs is
accomplished through the PHASE, ENBL,
BRAKE, and BMODE pins. See Table 1:
Table 1: Output Control Pins
ENBL
BMODE
PHASE OUT1 OUT2
1
0X LH
1
1X HL
0
X1 LL
0
X1 HH
0
00 H*L*
BRAKE
X
X
0
1
X
0
10 L*H*X
Reverse
Forward
Brake (low)
Brake (high)
Sync fast decay
Sync fast decay
Function
* As the current through the H-bridge approaches
zero, the outputs are tri-stated
nSLEEP Operation
Driving nSLEEP low puts the device into a low
power sleep state. In this state, all internal
circuits, including the gate drive charge pump,
are disabled, and the H-bridge outputs are
turned off. All inputs are ignored when nSLEEP
is active low. When waking up from sleep mode,
time (approximately 1ms) must pass before the
outputs will operate.
Fault
The MP6515 provides an nFAULT pin, which is
driven active low if any of the protection circuits
are activated. These fault conditions include
over-current, over-temperature, and over-
voltage. nFAULT is not driven low when a
current limit trip occurs. nFAULT is an open-
drain output and requires an external pull-up
resistor. When the fault condition is removed,
nFAULT is pulled inactive high by the pull-up
resistor.
Over-Current Protection
The over-current protection circuit limits the
current through each FET by reducing the gate
drive to the FET. If the FET remains in the
current limit condition for longer than the over-
current deglitch time, all MOSFETs in the H-
bridge will be disabled, and nFAULT will be
driven low. The driver will remain disabled for
t
OCP
, at which point it will be re-enabled
automatically. Over-current conditions are
sensed on both high and low side devices; i.e.,
a short to ground, supply, or across the motor
winding will result in an over-current shutdown.
Note that over-current protection does not use
the current sense circuitry used for PWM
current control, and it is independent of the
ISET resistor value.
Over-Voltage Protection
If the input voltage applied to VIN is higher than
the OVP threshold, the H-bridge output will be
disabled, and nFAULT will be driven low. This
protection is released when VIN drops to a safe
level.
Input UVLO Protection
If at any time the voltage on VIN falls below the
under-voltage lockout threshold, all circuitry in
the device will be disabled and the internal logic
will be reset. Operation will resume when VIN
rises above the UVLO threshold.
Thermal Shutdown
If the die temperature exceeds safe limits, all
MOSFETs in the H-bridge will be disabled, and
nFAULT will be driven low. Once the die
temperature has fallen to a safe level, operation
will resume automatically.
