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, VG,
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 VG does not exceed
14 V. Additionally, too low an inductance will cause large
instantaneous switching currents, which may damage the
device.
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
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
Two typical application schematics are shown in Figure 6.
and Figure 7.
V
= 3.0 V
V
= 2.5 V
M
DD
17550
47 µF
10 µF
L = 1.0 mH
VDD
VM
LX
OE
PSB
VG
2.2 µF
HBAF
HBAR
INAF
INAR
N
S
MCU
INBF
INBR
HBBF
HBBR
HBCF
HBCR
INCF
INCR
N
S
HBDF
HBDR
INDF
INDR
GND
Figure 6. Typical 17550 Application - Controlling Stepper Motors
17550
Analog Integrated Circuit Device Data
Freescale Semiconductor
10
FREESCALE [ Freescale ]
