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In many situations, we need to use MOSFETs configured ashigh-side switches. Many a times we need to use MOSFETs configured as high-side andlow-side switches. Such as in bridge circuits. In half-bridge circuits, we have1 high-side MOSFET and 1 low-side MOSFET. In full-bridge circuits we have 2high-side MOSFETs and 2 low-side MOSFETs. In such situations, there is a needto use high-side drive circuitry alongside low-side drive circuitry. The mostcommon way of driving MOSFETs in such cases is to use high-low side MOSFET drivers. Undoubtedly,the most popular such driver chip is the IR2110. And in this article/tutorial,I will talk about the IR2110.

You can download the IR2110 datasheet from the IR website. Here's the download link:

First let’s take a look at the block diagram and the pinassignments and pin definitions (also called lead assignments and leaddefinitions):

Fig. 1 - IR2110 block diagram (click on image to enlarge)

Fig. 2 - IR2110 Pin/Lead Assignments (click on image to enlarge)

Fig. 3 - IR2110 Pin/Lead Definitions (click on image to enlarge)

Notice that the IR2110 comes in two packages – 14 pinthrough-hole PDIP package and the 16-pin surface mount SOIC package.
Now let's talk about the different pins.

VCC is the low-side supply and should be between 10V and20V. VDD is the logic supply to the IR2110. It can be between +3V to +20V (withreference to VSS). The actual voltage you choose to use depends on the voltagelevel of your input signals. Here’s the chart:

Fig. 4 - IR2110 Logic '1' Input Threshold vs VDD (click on image to enlarge)

It is common practice to use VDD = +5V. When VDD = +5V, thelogic 1 input threshold is slightly higher than 3V. Thus when VDD = +5V, theIR2110 can be used to drive loads when input “1” is higher than 3 pointsomething volts. This means that it can be used for almost all circuits, sincemost circuits tend to have around 5V outputs. When you’re usingmicrocontrollers the output voltage will be higher than 4V (when themicrocontroller has VDD = +5V, which is quite common). When you’re using SG3525or TL494 or other PWM controller, you are probably going to have them poweredoff greater than 10V, meaning the outputs will be higher than 8V when high. So,the IR2110 can be easily used.

You may lower the VDD down to about 4V if you’re using amicrocontroller or any chip that gives output of 3.3V (eg dsPIC33). Whiledesigning circuits with the IR2110, I had noticed that sometimes the circuitdidn’t work properly when IR2110 VDD was selected as less than +4V. So, I donot recommend using VDD less than +4V.

In most of my circuits, I do not have signal levels whichhave voltages less than 4V as high and so I use VDD = +5V.

If for some reason, you have signals levels with logic “1”having lower than 3V, you will need a level converter / translator that willboost the voltage to acceptable limits. In such situations, I recommendboosting up to 4V or 5V and using IR2110 VDD = +5V.

Now let’s talk about VSS and COM. VSS is the logic supplyground. COM is “low side return” – basically, low side drive ground connection.It seems that they are independent and you might think you could perhapsisolate the drive outputs and drive signals. However, you’d be wrong. Whilethey are not internally connected, IR2110 is a non-isolated driver, meaning thatVSS and COM should both be connected to ground.

HIN and LIN are the logic inputs. A high signal to HIN meansthat you want to drive the high-side MOSFET, meaning a high output is providedon HO. A low signal to HIN means that you want to turn off the high-sideMOSFET, meaning a low output is provided on HO. The output to HO – high or low –is not with respect to ground, but with respect to VS. We will soon see how abootstrap circuitry (diode + capacitor) – utilizing VCC, VB and VS – is used toprovide the floating supply to drive the MOSFET. VS is the high side floatingsupply return. When high, the level on HO is equal to the level on VB, withrespect to VS. When low, the level on HO is equal to VS, with respect to VS,effectively zero.

A high signal to LIN means that you want to drive the low-sideMOSFET, meaning a high output is provided on LO. A low signal to LIN means thatyou want to turn off the low-side MOSFET, meaning a low output is provided on LO.The output on LO is with respect to ground. When high, the level on LO is equalto the level of VCC, with respect to VSS, effectively ground. When low, thelevel on LO is equal to the level on VSS, with respect to VSS, effectivelyzero.

SD is used as shutdown control. When this pin is low, IR2110is enabled – shutdown function is disabled. When this pin is high, the outputsare turned off, disabling the IR2110 drive.

Now let’s take a look at the common IR2110 configuration fordriving MOSFETs in both high and low side configurations – a half bridge stage.

Fig. 5 - Basic IR2110 circuit for driving half-bridge (click on image to enlarge)

D1, C1 and C2 along with the IR2110 form the bootstrapcircuitry. When LIN = 1 and Q2 is on, C1 and C2 get charged to the level on VB,which is one diode drop below +VCC. When LIN = 0 and HIN = 1, this charge onthe C1 and C2 is used to add the extra voltage – VB in this case – above thesource level of Q1 to drive the Q1 in high-side configuration. A large enoughcapacitance must be chosen for C1 so that it can supply the charge required tokeep Q1 on for all the time. C1 must also not be too large that charging is tooslow and the voltage level does not rise sufficiently to keep the MOSFET on.The higher the on time, the higher the required capacitance. Thus, the lowerthe frequency, the higher the required capacitance for C1. The higher the dutycycle, the higher the required capacitance for C1. Yes, there are formulaeavailable for calculating the capacitance. However, there are many parametersinvolved, some of which we may not know – for example, the capacitor leakagecurrent. So, I just estimate the required capacitance. For low frequencies suchas 50Hz, I use between 47µF and 68µF capacitance. For high frequencieslike 30kHz to 50kHz, I use between 4.7µF and 22µF. Since we’re using anelectrolytic capacitor, a ceramic capacitor should be used in parallel withthis capacitor. The ceramic capacitor is not required if the bootstrapcapacitor is tantalum.

D2 and D3 discharge the gate capacitances of the MOSFETquickly, bypassing the gate resistors, reducing the turn off time. R1 and R2are the gate current-limiting resistors.

+MOSV can be up to a maximum of 500V.

+VCC should be from a clean supply. You should use filtercapacitors and decoupling capacitors from +VCC to ground for filtering.

Now let’s look at a few example application circuits of theIR2110.

Fig. 6 - IR2110 circuit for high-voltage half-bridge drive (click on image to enlarge)

Fig. 7 - IR2110 circuit for high-voltage full-bridge drive with independent switch control (click on image to enlarge)

In Fig. 7 we see the IR2110 being used to drive a full bridge.The functionality is simple and you should understand it by now. A common thingthat is often done is that, HIN1 is tied/shorted to LIN2 and HIN2 istied/shorted to LIN1, enabling the control of all 4 MOSFETs from 2 signalinputs, instead of 4 as shown below in Fig. 8.

Fig. 8 - IR2110 circuit for high-voltage full-bridge drive with tied switch control - control with 2 input signals (click on image to enlarge)

Fig. 9 - Using the IR2110 as a single high-voltage high-side driver (click on image to enlarge)

In Fig. 9 we see the IR2110 being used as a single high-sidedriver. The circuit is simple enough and follows the same functionality describedabove. One thing to remember is that, since there is no low-side switch, theremust a load connected from OUT to ground. Otherwise the bootstrap capacitorscan not charge.

Fig. 10 - Using the IR2110 as a single low-side driver (click on image to enlarge)

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If you've had failures with IR2110 and had driver after driver, MOSFET after MOSFET get damaged, burn and fail, I'm pretty sure that it's due to you not using gate-to-source resistors, assuming of course that you designed the IR2110 driver stage properly. NEVER OMIT THE GATE-TO-SOURCE RESISTORS. If you're curious, you can read about my experience with them here (I have also explained the reason that the resistors prevent damage):

For further reading, you should go through this:

I have seen in many forums that people struggle with designing circuits with IR2110. I too had a lot of difficulty before I could confidently and consistently build successful driver circuits with IR2110. I have tried to explain the application and use of IR2110 thoroughly through explanation and plenty of examples and hope that it helps you in your endeavors with IR2110.