Analog Integrated Circuit Device Data
Freescale Semiconductor 9
17517
FUNCTIONAL DESCRIPTION
INTRODUCTION
FUNCTIONAL DESCRIPTION
INTRODUCTION
The 17517 is a triple totem-pole output H-Bridge power IC
designed to drive small dc motors used in portable
electronics. The 17517 can operate efficiently with supply
voltages as low as 2.0 V to as high as 6.8 V, and provide
continuos motor drive currents of 1.0
A while handling peak
currents up to 3.0
A. It is easily interfaced to low cost MCUs
via parallel 3.0 V- or 5.0 V-compatible logic. The device can
be pulse width modulated (PWM-ed) at up to 200 kHz. The
17517 can drive two motors in two directions one at a time; or
it can drive one motor in two directions and one solenoid with
synchronous rectification of freewheeling currents one at a
time. Two-motor operation is accomplished by hooking one
motor between OUTA and OUTB, and the other motor
between OUTB and OUTC. Motor
+ solenoid operation is
accomplished by hooking a motor between OUTA and OUTB
and placing a solenoid between OUTC and GND.
Table 5,
Truth Table, page 8, describes the operating states versus
the input conditions.
As shown in Figure 2, 17517 Simplified Internal Block
Diagram, page 2, the 17517 is a monolithic triple totem-pole
output bridge with built-in charge pump circuitry. Each of the
six MOSFETs forming the triple totem-pole output has an
R
DS(ON)
of ≤ 0.6 Ω (guaranteed by design). The IC has an
integrated charge pump and level shifter (for gate drive
voltages). Additionally, the IC has a built-in shoot-through
current protection circuit and undervoltage lockout function.
This IC has four operating modes: Forward, Reverse, Brake,
and Tri-Stated (High Impedance).
FUNCTIONAL PIN DESCRIPTION
DRIVER OUTPUT (OUTA, OUTB, OUTC)
These pins provide the connection to the internal power
MOSFET triple-totem-pole H-bridge of the IC.
GROUND (GND)
Power and signal ground pin.
CHARGE PUMP OUTPUT CAPACITOR (CRES)
This pin provides the connection for the external reservoir
capacitor (output of the charge pump). Alternatively, this pin
can also be used as an input to supply gate-drive voltage
from an external source via a series current-limiting resistor.
The voltage at the CRES pin will be approximately three
times the V
DD
voltage, as the internal charge pump utilizes a
voltage tripler circuit. The V
DD
RES
voltage is used by the IC to
supply gate drive for the internal power MOSFETs.
MOTOR DRIVE POWER SUPPLY (VM)
The two VM pins carry the main supply voltage and current
into the power sections of the IC. This supply then becomes
controlled and
/or modulated by the IC as it delivers the power
to the load attached between OUTA and OUTB.
The VM pins must be connected together on the printed
circuit board with as short as possible traces offering as low
impedance as possible between pins.
CONTROL SIGNAL INPUT AND ENABLE CONTROL
SIGNAL INPUT (IN1, IN1, EN1, EN2)
These pins are input control pins used to control the
outputs. These pins are 3.0 V/ 5.0 V CMOS-compatible
inputs with hysteresis. These pins work together to control
OUTA, OUTB, and OUTC (refer to
Table 5, Truth Table).
CHARGE PUMP BUCKET CAPACITOR (C1L, C1H,
C2L, C2H)
These two pairs of pins, the C1L and C1H and the C2L and
C2H, connect to the external bucket capacitors required by
the internal charge pump. The typical value for the bucket
capacitors is 0.1
µF.
CONTROL CIRCUIT POWER SUPPLY (VDD)
This pin carries the logic supply voltage and current into
the logic sections of the IC. V
DD
has an undervoltage
threshold. If the supply voltage drops below the undervoltage
threshold, the output power stage switches to a tri-state
condition. When the supply voltage returns to a level that is
above the threshold, the power stage automatically resumes
normal operation according to the established condition of
the input pins.
