Toshiba Photorelay Review - Getting to Know Photorelays

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Toshiba Photorelay Review - Getting to Know Photorelays [Copy link]

 I haven't paid much attention to photorelays before. Now let's take a look at what photorelays are. Here are some reference materials first. TLP3547_datasheet_en_20170420.pdf (386.46 KB, downloads: 7)

2018-9-14 11:35 上传

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The following figure is a schematic diagram of the internal circuit of the protagonist TLP3547. In short, this photorelay is a combination of an optocoupler module and a MOSFET switch. Let's take a look at the official feature description. Features (1) Normally opened (1-Form-A) (2) OFF-state output terminal voltage: 60 V (min) (3) Trigger LED current: 5.0 mA (max) (4) ON-state current: 5 A (max) (A connection) (5) ON-state resistance: 50 mΩ (max) (A connection) (6) Isolation voltage: 2500 Vrms (min) Brief explanation 1. Normally open mode 2. Because there is a MOS switch tube inside, there is a maximum operating voltage limit of 60V. This is no problem for conventional 5V, 12V, and 24V electrical equipment. As for higher voltages, such as AC220, don't try it. 3. The maximum front-end diode trigger current is 5mA. If configured in low-level conduction mode, most general MCUs can basically drive it. 4. The maximum conduction current is 5A (Type A connection, which will be explained in detail later). This is also completely sufficient for conventional applications. 5. The maximum on-resistance is 50mΩ, which is quite small. The smaller the internal resistance, the smaller the heat generation, and the corresponding lifespan and reliability will be better. This photorelay actually has multiple application modes. The A Connection in the figure below is the schematic diagram of the evaluation board. This mode can work in both AC and DC, and has a large degree of freedom. B Connection and C Connection can only work in DC mode. C Connection can achieve a maximum operating current of 10A. However, this evaluation board does not bring out pins 6 and 7, so this connection method cannot be directly implemented The figure below is the accompanying instruction document, but there is a small problem with the figure on the right. The 1.5k resistor on the back of the evaluation board is actually connected in series in the circuit, and then output to the outside as pins 1 and 2, that is, the schematic diagram of A Connection is more accurate

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Thank you for sharing, I learned a lot.