17550 Datasheet, PDF (10/15 Pages) Freescale Semiconductor, Inc – Quad H-Bridge Micromotor Driver with DC/DC Boost Converter

TYPICAL APPLICATIONS
INTRODUCTION
TYPICAL APPLICATIONS
INTRODUCTION
The 17550's built-in DC / DC converter must be connected
to an external inductor, rectifier, and filter capacitor. This
step-up converter generates the gate-drive voltage, V_G,
required by the internal gate driver circuits. Although there is
some latitude in selecting the values for the external
component, care must be taken that V_G does not exceed
14 V. Additionally, too low an inductance will cause large
instantaneous switching currents, which may damage the
device.
Important Do not use an inductance lower than 330 µH.
To attain high-efficiency operation, the rectifier should be
a Schottky diode, and the filter capacitor should be of the low
Equivalent Series Resistance (ESR) type. Attention should
be paid to proper switch mode power supply PCB layout
practice. Some experimentation may be required to
determine optimal external component values. The
recommended starting values are L = 1.0 mH, C = 2.2 µF.
The DC / DC converter includes its own internal oscillator
and does not require an external clock input.
TYPICAL APPLICATION
Two typical application schematics are shown in Figure 6.
and Figure 7.
47 µF
V_M = 2.5 V V_DD = 3.0 V
17550
VM
VDD
10 µF
L = 1.0 mH
LX
OE
PSB
VG
2.2 µF
MCU
INAF
INAR
HBAF
HBAR
INBF
INBR
HBBF
HBBR
INCF
INCR
HBCF
HBCR
INDF HBDF
INDR HBDR
GND
N
S
N
S
Figure 6. Typical 17550 Application - Controlling Stepper Motors
17550
10
Analog Integrated Circuit Device Data
Freescale Semiconductor