Toshiba Photorelay Review - DC Characteristics Test

tianshuihu

Toshiba Photorelay Review - DC Characteristics Test [Copy link]

 Today, let's test the DC characteristics of the TLP3547F photorelay: 1. The on-state voltage and current of the internal diode of the photorelay 2. The on-state internal resistance of the photorelay Test schematic and test conditions First is the test schematic, which is simply drawn by hand [attach]376227 [/attach] In addition to the photorelay module, it mainly includes: a 5V power supply (power bank), two small bulbs (6V 5W, rated internal resistance is about 4.16Ω), and a 3.2V signal source [attach]376226 [/attach] Test related instruments and meters Agilent oscilloscope DSO-X 3034A, Agilent signal source 33522A, digital multimeter UT61E (four and a half digits), USB power meter Test of the on-state voltage and current of the internal diode of the photorelay The output signal of the signal source is: -3.2V ~ +3.2V sawtooth wave, 5Hz Test point bitmap The oscilloscope observes 3 channel waveforms at the same time 1ch: Ua-b (input signal, yellow curve) 2ch: Ue-b (waveform at both ends of the diode, green curve) 4ch: Ud-c (waveform at the output end of the photorelay, pink curve) PS. The 4ch waveform in the figure is the reverse waveform, which is more convenient for comparison. From the waveform in the figure, we can see that at the beginning, since the diode has not been turned on (reverse cutoff), the internal resistance is very large, and the waveform at both ends is basically consistent with the signal source waveform; the signal source voltage rises to about 1.4V and gradually stabilizes, and no longer rises with the increase of the signal source voltage; but the photorelay is actually turned on after the diode has been turned on for a period of time. This specific time delay will be tested in the dynamic characteristics later. It can be concluded that the turn-on voltage of the optocoupler diode is approximately Uf = 1.41V When driven by 3.2V, the working current of the diode is approximately If = Ures / Rres = (3.2V-1.41V)/1.5kΩ = 1.2mA Photorelay MOSFET on-resistance test The output signal of the signal source is: a square wave signal with an amplitude of 3.2V and a duty cycle of 50%, 0.2Hz The reading is taken when the photorelay is turned on and stable, as shown in the figure below At this time, the on-current Ion = 0.828A Ud-c = 19.69mV (multimeter directly measures the voltage of TLP3547F 5 and 8 pins) R = U / I = 0.01969V / 0.828A = 0.023 Ω, that is, the on-resistance is about 23mΩ. Conclusion: According to the official technical documents, the internal LED is relatively easy to drive, and it can be turned on at about 1.4V. Under the conventional 3.3V (3.2V is used in the actual measurement) driving conditions, the internal LED If=1.2mA, it is much larger than the typical switching current of 0.28mA. The margin left by this evaluation board is quite large, and it can be easily driven by a general MCU. The measured on-resistance is 23mΩ, which is very close to the typical value of 22mΩ in the manual. This internal resistance is quite low. Great! To be continued......

tianshuihu

Toshiba Photorelay Review - Dynamic Characteristics Test

alan000345

The test was really good

fsyicheng

:Hard goods, worth browsing