NSD-2101 Datasheet, PDF (8/22 Pages) ams AG – Piezo Motor Driver ASIC for SQL-RV Series Reduced Voltage SQUIGGLE® RV and UTAF™ Motors

NSD-2101
Data Sheet - Detailed Description
The rise and fall time definition is shown in Figure 5. Time between crossing 10% and 90% threshold of minimum VDD is measured, 10% to 90%
for rise time and 90% to 10% for fall time. A full bridge switching cycle will take longer.
Figure 5. Rise / Fall Time Definition
V(half-bridge)
VDD = 2.3V
90%
10%
0V
tr
t
tf
In Figure 6, the effect of current limit in the output drivers is shown. Each half-bridge output can deliver 1000mA.
Figure 6. Output Driver Current Limit
I(half-bridge)
Ilim = 1600mA
Ilim = 1000mA
0mA
typ 1300mA
t
7.2 Power Dissipation Control
Following techniques are implemented to keep the system and on-chip power dissipation low.
Selectable half bridge mode depending on input supply voltage
Selective charge control for full bridge mode
Hybrid Control for full bridge mode
Table 7. Power Dissipation Control
Symbol
Parameter
Conditions
Min Typ Max Units
Selectable half-bridge
HB_thr
Rising Threshold
When half-bridge mode is enabled then the output driver 4.3 4.5
4.7
V
will switch to half-bridge drive depending on input supply
voltage. Typical system power dissipation can be reduced
down to 25% of standard full-bridge drive. When VDD is
HB_thf
Falling Threshold
higher than 5.0V only half bridge mode should be used to
avoid exceeding max total power dissipation of 1W. A
4.2
4.4
4.6
V
typical hysteresis of 100mV is implemented to increase
immunity against supply disturbances.
Selective charge control for full-bridge
SCC_PDS
By adding an additional state in the full bridge switching
Power dissipation saving scheme the power dissipation can be reduced due to the 30
fact that the effective voltage on the capacitor is reduced.
50
%
Hybrid Control for full-bridge
PS_PDS
Power dissipation saving
With this technique the power dissipation can be reduced
by switching periodically from full-bridge to half-bridge
mode. Power saving in comparison to standard full-bridge
drive is mainly depending on duty cycle between half-
bridge and full-bridge. Hybrid Control is also used for
speed control.
75
%
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