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400V:200mV = (R2＋R3) + 390Ω:39 Ω
200mV × (R2＋Ｒ3) + 200mV × 390Ω = 400V × 390Ω
When R2 and R3 are selected from E24 series, R2 = 390 Ω and R3 = 390 Ω.
* R2 and R3 are connected in series to ensure creepage distance of resistors.
Eexample 2:
Sensing error : below 1%
Equivalent input resistor of TLP7820 (R
R1:R1 // R
0.99 = 80kΩ/(R1+80kΩ)
0.99 × R1 + 0.99 × 80kΩ = 80 kΩ
When R1 is selected from E24 series, R1 = 750 Ω.
Applied voltage : 400 V
Detecting voltage : 200 mV
400V:200mV = （R2＋R3) + 750Ω:750Ω
200mV × (R2＋R3) + 200mV × 750Ω = 400V × 750Ω
When R2 and R3 are selected from E24 series, R2 = 750 Ω and R3 = 750 Ω.
* R2 and R3 are connected in series to ensure creepage distance of resistors.
The tolerances of R1, R2, and R3 should be considered to calculate actual voltage-sensing error.
4.2 Test mode considerations
The TLP7820 enters test mode when either the V
2V = 3V when V
= 5V). Don't use the TLP7820 in such a condition.
DD1
5. Simulation
5.1 Basic operation
This section shows the simulation results for verifying the basic operation of the TLP7820. Figure
5.1 shows the simulation circuit under the following conditions:
∎ Simulation conditions
· V
of IC1: 5V
DD1
· V
of IC1 and V+ of IC2: 3.3V
DD2
· Vin
Input voltage (10-kHz sine wave with 0.2Vp-p)
© 2018
Toshiba Electronic Devices & Storage Corporation
∴R2＋Ｒ３ ≈ 780 kΩ
= R1:(R1×80kΩ) / (R1+80kΩ) = 1:0.99
i
∴R2+R3 ≈ 1.5 MΩ
) : 80 kΩ
i
∴R1 ≈ 808 Ω
or V
pin exceeds (V
IN+
IN-
11 / 19
RD014-RGUIDE-01
-2) volts (e.g., 5V -
DD1
2018-03-15
Rev. 1
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