The diode whose forward voltage is 0 (zero) equipped with characteristics of passing current in only one direction is called ideal diode.
An IC (integrated circuit) that reproduces the characteristics of this ideal diode is called ideal diode IC. As the ideal diode has no forward voltage drop or current leakage, it has no forward voltage drop, loss, or current leakage that have occurred in discrete diode.
With an actual ideal diode IC, it is possible to completely eliminate forward voltage or current leakage because there are on resistance and current leakage of FET in IC, however, forward voltage drop and power loss can be considerably reduced compared to diode.
Advantages / Disadvantages of Ideal Diode IC
The ideal diode IC has various advantages compared to discrete diode.
Advantages and disadvantages of ideal diode IC are summarized below.
Advantages
- Low loss due to such a small VF & low current leakage (XC8110/XC8111 : VF=20mV)
- As VF is small, output voltage fluctuation is small and it contributes to stable operation of system
- Equipped with various built-in protection functions
- Small package
Disadvantage
- Number of products is small / less compatible compared to discrete diode
You may not be able to realize how much of a difference there is from a diode. Let's compare the differences between diode and ideal diode in each item.
① Current leakage / forward voltage
② Various protection functions
| Protection Function | Discrete Diode | Ideal Diode |
|---|---|---|
| Inrush current limit | Without With | With |
| Current limit | Without With | With |
| Overheat protection | Without With | With |
Conclusion
Using the ideal diode IC can considerably reduce voltage drop and power loss compared to those of discrete diode.
As the protection functions are mounted in addition to characteristics, it is possible to ensure safer circuit design.