MP6506 –2.7V-TO-15V, 500mA, STEPPER MOTOR DRIVER
MP6506 Rev. 1.0 www.MonolithicPower.com 9
5/22/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2014 MPS. All Rights Reserved.
OPERATION
The MP6506 is a motor driver that integrates 8
N-channel power MOSFETs for dual, internal full-
bridges with 500mA output current capability over
an input voltage range of 2.7V to 15V. It can
drive a stepper motor, or two DC motors.
The motor output current can be controlled by an
external pulse width modulator (PWM).
The MP6506 includes the following fault
protections: under-voltage lockout (UVLO) and
over-temperature protection (OTP).
It also provides a low-power sleep mode.
External PWM Current Control
The motor current can be regulated by applying
external PWM signals on the input pins AIN1,
AIN2, BIN1 and BIN2. For phase A, the AIN1 and
AIN2 input pins control the state of the AOUT1
and AOUT2; similarly for phase B, thee BIN1 and
BIN2 input pins control the state of the BOUT1
and BOUT2.
Table 1 shows the input signal logic and bridge
output state.
Table 1: Full-Bridge Gate Logic
A/BIN1 A/BIN2 A/BOUT1 A/BOUT2
L L
High
Impedance
High
Impedance
L H GND VIN
H L VIN GND
H H GND GND
The winding’s inductive current ramps up when
the high-side MOSFET is on and freewheels
during the high-side MOSFET’s off time to cause
the recirculation current.
There are two modes for this recirculation current:
slow decay and fast decay, both of which are
shown in Figure 2 for forward operation and
Figure 3 for reverse operation.
Figure 2: Forward Operation
Figure 3: Reverse Operation
For slow decay mode, the current circulates
through the two low-side MOSFETs. For fast
decay mode, the current flows through the body
diodes of the other diagonal two MOSFETS.
To configure the MP6506 for fast decay mode,
apply the PWM signal to one input pin and keep
the other input pin low; for slow decay mode,
apply the PWM signal to one input pin and keep
the other input pin high. See Table 2 for more
configuration details and Figure 4 for detailed
waveforms.
