LV8491CT Datasheet, PDF (18/20 Pages) Sanyo Semicon Device – Piezo Actuator Driver IC

Actuator drive waveform settings :
LV8491CT
Configuration of piezoelectric actuator drive waveform
f = 1 period
Ta
off
Tb
Drive parameter settings
Since the counter starts from zero,
a value minus 1 is set.
RST = Number of clock pulses in period minus 1
GTAS =
Ta + 1
Ta-1+2 = Ta+1
since the waveforms start after two clock pulses.
Rises here after two clock pulses from reference.
GTBR =
GTAS + off
Waveform start
reference point
GTBS =
GTBR + Tb
The drive waveforms are set using four parameters: RST, GTAS, GTBR and GTBS.
RST : Parameter determines the period, and sets the reference clock pulse count minus 1.
GTAS : Parameter determines the time taken for the gate signal A to the falling edge from the reference point.
Since the signal raises after two clock pulses from the reference, the Ta reference clock cycle count plus 1 is
set.
GTBR : Parameter determines the time taken for the gate signal B to the rising edge from the reference point.
It sets the value obtained by adding the reference clock pulse count during the time from GTAS to “off.”
GTBS : Parameter determines the time taken for the gate signal B to the falling ewdge from the reference point.
It sets the value obtained by adding the reference clock pulse count during the time from GTBR to “Tb.”
[Example of settings] When setting reference clock to 10MHz, period to 13μs, Ta to 2.0μs, off to 0.3μs, and Tb to 3.0μs
Since the reference clock time is 0.1μs :
The period is 130 clks. → Specify 129 (RST value of 130 -1).
Ta is 20 clks. → Specify 21 (GTAS value of 20 + 1).
off is 3 clks. → Specify 24 (GTBR value of 21 + 3).
Tb is 30 clks. → Specify 54 (GTBS value of 24 + 30).
No.A1760-18/20