TLP250 (MOSFET IGBT DRIVER)
Pin layout of TLP250 is given below. It is clearly shown in figure that led at input stage and photo detector diode at output stage is used to provide isolation between input and ouput. Pin number 1 and 4 are not connected to any point. Hence they are not in use. Pin 2 is anode point of input stage light emitting diode and pin 3 is cathode point of input stage. Input is provided to pin number 2 and 3. Pin number 8 is for supply connection. Pin number 5 is for ground of power supply.
- Pin number one and four is not connected to any point physically. Therefore they are not in use.
- Pin number 8 is use to provide power supply to TLP250 and pin number 5 is ground pin which provides return path to power supply ground. Maximum power supply voltage between 15-30 volt dc can be given to TLP250. But it also depends on temperature of environment in which you are using TLP250.
- Pin number 2 and 3 are anode and cathode points of input stage LED. It works like a normal light emitting diode. It has similar characteristics of forward voltage and input current. Maximum input current is in the range of 7-10mA and forward voltage drop is about 0.8 volt. TLP250 provides output from low to high with minimum threshold current of 1.2mA and above.
- Pin number six and seven is internally connected to each other. Ouput can be taken from either pin number 6 and 7. Totem pole configuration of two transistor is used in TLP250. In case of high input , output becomes high with output voltage equal to supply voltage and in case of low input, output become low with output voltage level equal to ground.
- Mosfet driver TLP250 can be used up to 25khz frequency due to slow propagation delay.
This all about pin configuration and working of TLP250. Now i will talk about how to used isolated mosfet driver tlp250 as low side MOSFET driver and high side mosfet driver.
TLP250 as a low side MOSFET driverCircuit diagram of low side mosfet driver using tlp250 is shown below. In this circuit diagram, tlp250 is used as non inverting low side mosfet driver. you should connect an electrolytic capacitor of value 0.47uf between power supply. It provide protection to tlp250 by providing stabilize voltage to IC.
As shown in figure above input is drive signal that drives the output. Vin is according to signal ground. It should not be connected with supply ground and output ground. It is clearly shown in above figure TLP250 and load ground is referenced to the power ground and it is isolated from input signal reference ground. When input is high, MOSFET Q1 get high signal from TLP250 and it is driven by power supply and current flows through the load. When input is low, MOSFET Q1 get low signal from TLP250 output pin and mosfet Q1 remains off and there is no current flow to load. Value of supply voltage ranges between 10-15 volt. Input resistor at gate of MOSFET is used depend on amplitude of input signal. Usually input signal is provided through microcontroller and microcontroller input signal level is in the order of 5 volt. Capacitor C1 is used as decoupling capacitor.
TLP250 as a high side MOSFET driver
Circuit diagram of MOSFT driver tlp250 used as high side driver is shown below. It is used as non inverting high side mosfet driver. Because input signal ground is connected to cathode of input stage light emitting diode. Therefore it is used as a non inverting high side mosfet driver.
In high side configuration there are three grounds as shown in figure above. Ground of input signal, ground of supply voltage and ground of power supply voltage. Remember that while using TLP250 as high side MOSFET driver, all grounds should be isolated from each other.