Diodes Incorporated Reveals 2A Load Switch Aimed to Improve High-Side Load Switch ReliabilityOctober 25, 2019 by Gary Elinoff
The AP22913 features slew-rate control and true reverse-current blocking for single-channel load switching.
Diodes Incorporated has announced a new single P-channel MOSFET power switch that features slew-rate control and true reverse-current blocking (TRCB). The AP22913—a 2.0-amp load switch—is designed to increase reliability for high-side load switching applications.
The AP22913 high-side load switch. Image from Diodes Incorporated
Single-channel, high-side load switches are often employed to safely apply or remove power to loads. Protecting peripherals powered through USB ports is an important use case for this product because output capacitors in the range of 100 µF are often present.
This opens the possibility of reverse-biasing the load switch, which might lead to reverse current traveling from the load device back to the source. Were this to happen, the device components or the cable could incur damage. The AP22913A load switch incorporates TRCB (true reverse-current blocking), which mitigates this possibility.
What is True Reverse-Current Blocking?
Reverse current occurs when a device being powered is temporarily at a higher voltage potential than is the source powering it. This can occur when the source voltage turns off, and the device being powered (perhaps because of internal capacitance) momentarily retains part or all of its operating voltage.
TRCB prevents this from occurring when the power is shut off. It also prevents reverse current during turn-off and turn-on.
Options and Applications
The AP22913 is available in two options:
The AP22913CN4-7, housed in the X-WLB0909-4 package
The AP22913W6-7, which is available in the SOT26 package
The AP22913W6-7. Image used courtesy of Digi-Key
The AP22913 load switch device is suitable for applications including:
- Portable units
- Medical devices
- Navigation devices
- Advanced notebooks
The AP22913 load switch operates over a range of 1.4V to 5.5V, which covers systems operating at the popular 1.8, 2.5, 3.3, and 5.0-volt levels. Typical RDS(ON) is 92mΩ at 1.5V and 54mΩ at 5.0V. It can support a maximum load current of 2.0 amps.
Functional block diagram of the AP22913 load switch. Image from Diodes Incorporated
The turn-on slew rate of the device is internally controlled. This allows for a soft-start feature ideal for sensitive loads.
Typical applications circuit of the AP22913 load switch. Image from Diodes Incorporated
The VIN and VOUT terminals are completely isolated internally, which ensures TRCB when the load switch is disabled and in its off state.
Around the Industry
It’s not surprising that Diodes Incorporated has many competitors for such an important type of device as a TRCB load switch.
The TPS22916xx family of load switches from Texas Instruments features TRCB and operates over a range of 1V to 5.5V, with a maximum continuous current of 2 amps. The typical on-resistances are 60, 100, and 200 mΩ at 5.0, 1.8, and 1.0 volts, respectively.
The AOZ1353DI from Alpha & Omega Semiconductor is a load switch that also features TRCB. The input voltage range is from 3.4V to 5.5V. The unit sports a typical on-resistance of 40mΩ, and it has a 3.5-amp current capacity.
Have reverse currents ever affected one of your projects? Share your experiences in the comments below.