Hello all
I am working on making a H bridge with a IR2101 gate driver IC and two IRFZ44N MOSFETS, I have made the circuit that is shown on the datasheet. 9 volts on the VSS of the IC and 14 Volts on the FETS. everything seems to work fine besides the High side HO pin. It stays on all the time, the LO pin works fine and turns on and off the low side MOSFET but the HO pin keeps the high side MOSFET on all the time even if there is nothing connected to the HIN pin that controls the HO pin. someone please help ive been scratching my head for weeks
My apologies VCC I meant to say
Which voltage do you measure between VB and VS? That's the range for the high side gate voltage.
A load may be required for proper operation?
the photo has been updated as you requested. the diod is a 1N4004. I will also check tomorrow
For more information on the chip see this page.
I understand how the chip works my problem is this the HO pin is stuck on all the time. the person even stated in the post "HIN is the logic level input to control the top MOSFET (HO). When high, the top MOSFET is switched on" yes thats correct BUT when HIN is low HO stays on? this is what I am confused about. is it my capacitor?
There exist restrictions to the high side switch, see the last paragraph
Important to realise that the top MOSFET cannot be on for a long time. C6 will discharge.
Also, in every cycle, the bottom MOSFET must be switched on to recharge C6 before the top MOSFET is used again.
Instead of a H-bridge connection between both MOSFETs a load from the high side driver to Gnd seems required.
Hi,
When asked for an update, please do it in a NEW post, going back and editing an old post will make it difficult for anyone else to follew.
Have you checked Hin to see if it is HIGH all the time.
Please a full circuit showing your connection the Arduino controller and your code?
What Arduino controller are you using?
Please post your code.
Do you have code that JUST tests the outputs?
If not then write one and check Hin and HO pins.
A picture of your project would help to.
Thanks.. Tom... 
Hello
I have checked to see if HIN is on all the time and it indeed is. even on new chips out of the box. The site in which I created the circuit does not have the option to add a microcontroller but the pin I am using is 11 and 10. my code is just a simple blink code. all of this is on breadboard
int potPin = A0; // select the input pin for the potentiometer
int val = 0; // variable to store the value coming from the sensor
void setup() {
pinMode(10, OUTPUT);
pinMode(11, OUTPUT); // declare the ledPin as an OUTPUT
}
void loop() {
val = analogRead(potPin) + 100;
digitalWrite(10, HIGH); // turn the ledPin on
delayMicroseconds(val); // stop the program for some time
digitalWrite(10, LOW); // turn the ledPin off
delayMicroseconds(val);
digitalWrite(11, HIGH); // turn the ledPin on
delayMicroseconds(val); // stop the program for some time
digitalWrite(11, LOW); // turn the ledPin off
delayMicroseconds(val); // stop the program for some time
}
arduino Uno R3. everything on the circuit is what is have on the board.
Hi,
Thanks for that, but I need a picture with the UNO and driver connections in it and a circuit diagram.
Check if pins 10 and 11 go HIGH/LOW at the UNO.
Then remove the Mosfet drive IC and check pin 10 and 11 and where the Hin and Lin pins were connected at the board.
Have you got a load on the output of the Mosfets?
If not try a 1K resistor.
Thanks.. Tom...
Hello
I checked the pins on the Arduino and they are going from high to low. Also I can completely disconnect the Arduino from the IC and HO will still stay on. My load is a small 12 volt lightbulb
Hi,
If you have pin 10 and 11 connected to Hin and Lin and with no driver plugged in and you have Hin HIGH all the time at the driver., you have a wiring problem.
Please pull the driver out and check with the UNO still connected.
Please check that pin 10 and pin 11 are really going to the Hin and Lin pins?
You have got the COM of the driver connected to the gnd of the controller?
Tom...
Hello.
Indeed pin 11 is going to HIN and 10 is going to LIN. Pin 10 and 11 are functioning perfectly fine. Only LIN seems to be working and switching on and of the one mosfet. As I mentioned HO is staying on all the time. What I was saying was I can disconnect 11 from HIN and HO will still be on
Hi,
Question do you really have the MOSFETs connected as in post #1?
They are the other way in the datasheet.
You have Drain and Source swapped.
They are N-CH MOSFETs, Drain is positive with respect to the Source for them to function.
Chech also the pinouts of your MOSFET.
PLEASE reverse engineer your project and draw a circuit diagram.
Mkae sure you label pins including Drain (D), Gate (G) and Source(S).
Tom...
Hello
Maybe I am reading the mosfet symbol wrong. For the high side mosfet the positive goes to the drain and the load goes to the source? And for the low side it's reversed? Is this correct?
Yes, as in the circuit in post#19.
When you say HO stays HIGH, what voltage, if you can see Hin going HIGH/LOW what voltage does HO measure at?
Tom...
