CPC1560 Datasheet, PDF (11/14 Pages) Clare, Inc. – Solid State Relay with Integrated Current Limit

5.6 Rise and Fall Times
The CPC1560 has rise and fall times that are primarily
limited by internal parasitic elements of the device; the
load components only play a secondary role. This can
be appreciated in the turn-off graph of an application
circuit operating at 45V, where the slope of the load
voltage starts scooping down into a more capacitive
shape after approximately 15 volts.
CPC1560
DC-Only Application Circuit
Resistive Load Turn-Off Characteristics
(Supply=45V_DC, R_LOAD =75Ω)
50
1.0
t_RISE=46μs
V_L
40
0.8
I_L
30
0.6
20
0.4
10
0.2
0
0.0
-80 -60 -40 -20 0 20 40 60 80
Time (μs)
CPC1560
5.7 Over-Voltage Protection
5.7.1 Stored Energy in the Load
During the CPC1560’s switching periods, energy is
transferred between the load components, the
CPC1560 device, and, if used, the over-voltage
protection circuitry.
When the output switch turns off, inductive loads
(L_LOAD) transfer their stored energy into the MOSFET
switches, the load capacitance, and the over-voltage
protector. (See the turn-off graph for a 45V inductive
load application circuit.)
When the output switch turns on, the energy in the
load inductor is zero, and the load capacitor (C_LOAD)
must transfer its stored energy into the MOSFET.
CPC1560
DC-Only Application Circuit
Inductive Load Turn-Off Characteristics
(Supply=45V,
R
LOAD
=75Ω,
L=
LOAD
630μH)
50
1.0
V_L
40
0.8
I_L
30
0.6
20
0.4
10
0.2
0
0.0
-80 -60 -40 -20 0 20 40 60 80
Time (μs)
R00F
PRELIMINARY
11