This application note discusses the features and characteristics of Micropower High Side MOSFET Drivers, including the VGS ratings of standard N-channel and logic-level N-channel MOSFETs. It also explores the challenges and considerations in selecting and designing high side switches.
The document introduces the LTC1155, a dual micropower MOSFET driver designed to fully enhance logic-level N-channel switches by generating a 12V gate drive voltage from a standard 5V supply. This capability eliminates the need for external components and allows for highly efficient power management in portable electronic equipment such as notebooks and medical instruments.
The text compares logic-level and standard N-channel MOSFETs, detailing their voltage ratings and selection criteria. It provides specific application circuits for powering large capacitive loads to prevent supply glitches, creating bidirectional switches using back-to-back MOSFETs, and extending the driver's operation range up to 28V.
| Supply Current (Switch Enhanced) | typically 85 µA |
|---|---|
| Supply Current (Standby Mode) | 8 µA |
| Gate Drive Voltage Generated | 12V from a 5V rail |
It generates 12V from a 5V rail to fully enhance logic-level N-channel switches with no external components required.
It enables switch efficiencies in the 98% to 99%+ range by using low-drop N-channel MOSFET switches instead of P-channels.
Yes, it can operate in the 18V to 28V range by clamping the supply pin to 18V.