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Optical coupling selection
Mar 17, 2017

When the optocoupler isolated circuit design must be correct optical Coupler types and parameters, selection principles are as follows:

(1) due to photo-coupler signal one-way transmission device, and circuit data transmission is bi-directional, circuit board size required, and circuit design requirements, choose single-chip integrated multi-channel optocoupler devices.

(2) photo-coupler current transfer ratio (CTR) allowed range is not less than 500%. When you CTR<500%, LED for optical coupling requires a large current (>5.0 mA) in order to ensure that errors do not occur in transmitting signals, which can increase the power of optical coupling.

(3) optocoupler transmission speed is also choosing optocoupler must adhere to the principle of one of the optocoupler switching speed is too slow, unable to respond correctly to input level, affects the circuit to work properly.