DC1197A - Demo Manual

DEMO CIRCUIT 1197
QUICK START LT3572
GUIDE
LT3572
Dual Full-Bridge Piezo Driver
With 900mA Boost Converter
DESCRIPTION
Demonstration circuit 1197 features
LT3572 in a 800kHz step-up converter circuit, designed for 30V
output from a 3V to 5V input. The
high output voltage is then used by
the dual full-bridge drivers. The
LT3572 is capable of independently
driving two Piezo motors with two
input PWM signals. The motors respond accordingly based on the duty
cycle and the frequency of the PWM
signals. The drivers operate in an
H-bridge fashion, where the OUTA
and OUTB pins are the same polarity
as the PWMA and PWMB pins respectively and the OUTA and OUTB are
inverted from PWMA and PWMB respectively. A PGOOD pin indicates when
Performance Summary for Piezo Driver
PARAMETER
Minimum Input Voltage
Maximum Input Voltage
Output Voltage VOUT
Typical Load
Typical Switching Frequency
the output of the step-up converter
is in regulation and the Piezo
drivers can start switching. The
step-up converter and both Piezo
drivers have their own shutdown
control.
The LT3572 datasheet gives a complete description of the part, operation and application information. The datasheet must be read in
conjunction with this quick start
guide for demo circuit 1197.
Design files for this circuit board
are available. Call the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT and PowerPath are trademarks of Linear Technology Corporation.
( TA = 25oC )
CONDITION
VALUE
3V
5V (Note 1)
30V +/-3%
2 TULA50 Piezo Motors
800kHz
Note 1: Maximum input voltage of the demo circuit is limited by the voltage rating of the input
capacitor.
1
LT3572
QUICK START PROCEDURE
Demonstration circuit 1197 is easy
to set up to evaluate the performance of the LT3572. Refer to
Figure 1 for proper measurement
equipment setup and follow the procedure below:
NOTE. When measuring the input or
output voltage ripple, care must be
taken to avoid a long ground lead
on the oscilloscope probe. Measure
the input or output voltage ripple
by touching the probe tip directly
across the Vin or Vout and GND terminals. See Figure 2 for proper
scope probe technique.
1. Place
JP3, JP4 and JP5 on the
ON position:
2. Connect
2
the
two
TULA50
Piezo
Motors to JP1 and JP2.
3. With power off, connect the in-
put power supply to Vin and GND.
4. Turn on the power at the input.
NOTE. Make sure that the input
voltage does not exceed the maximum input voltage.
5. Check
for
voltage.
the
proper
output
6. Apply
PWM signals, typically
switching between 0V and 2V, to
the PWMA and PWMB pins.
7. Adjust
the duty cycles of the
input PWM signals and observe
the movement of the motors.
LT3572
Figure 1. Proper Measurement Equipment Setup
GND
VIN
Figure 2. Measuring Input or Output Ripple
3
LT3572
4
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