TD3082 Solid State Optronics, TD3082 Datasheet - Page 3

• Manufacturer Part Number: TD3082
• Description: Zero-Volt Switching Triac Driver
• Manufacturer: Solid State Optronics

ZERO-VOLT SWITCHING
Figure 1 shows the sequence of zero-volt switching operation. At Stage 1, an input signal is applied to the relay. The relay will not turn on
until the threshold voltage of 5V is reached. Once this point is reached (Stage 2), SCR #1 (designated as the SCR which controls positive AC
voltage) turns on. However, SCR #1 only conducts for an instant, as the cycle quickly crosses zero. At this point (Stage 3), SCR #1 will turn
off and SCR #2 (negative AC voltage) turns on. Likewise, at the next zero cross (Stage 4), SCR #2 will turn off and SCR #1 conducts again.
Even though the input signal is terminated at Stage 5, the relay will continue to conduct (typical SCR behavior) until Stage 6, when SCR #1
crosses zero and ceases to conduct. Please note that turn on can likewise begin on the negative phase of the AC cycle with a -5V threshold,
though only the positive phase is shown here.
PERFORMANCE DATA
This solid state relay has been designed with a driver circuit that controls the operation of two back-to-back silicon controlled rectifiers (SCRs),
each responsible for one half of the AC cycle. If an AC signal is examined, the turn on, turn off and zero-volt switching can be seen. Figure 1
shows a typical 60 Hz, 120Vac signal with a corresponding relay input signal:
rev 1.0
120
100
80
60
40
20
0
Threshold
-40
Typical Load Current vs. Temperature
Input Signal
5 V
-20
Tem perature (C)
0
TD3082
20
40
1
3
Relay Input Signal is
Turned On.
SCR #1 Turns Off,
SCR #2 Turns On
at Zero Volts.
60
80
2
SCR #1 Turns On when
5V threshold is reached.
50
40
30
20
10
0
800 810 820 830 840 850 860 870
4
N = 100, Ambient Temperature = 25°C
Typical Blocking Voltage Distribution
SCR #2 Turns Off,
SCR #1 Turns On
at Zero Volts.
Blocking Voltage (V)
5
TD3082
Relay Input Signal is
Turned Off.
TD3082
6
SCR #1 and Relay Turn
Off at Zero Volts.
Zero-Volt Switching
Solid State Optronics, Inc.
www.ssousa.com
Triac Driver
1.888.377.4776