How to Choose a Power Path Selector
Abstract
Maxim has several power path selectors. Some have integrated overvoltage protection, and some have manual reset inputs. The path selectors can auto select the switch depending on the input voltage or the user can enable the switch path manually.
This application note gives an overview of our power path selectors to help customers choose the power path selector that suits their application.
The MAX14713/MAX14714 compact 6A smart power path selectors auto-select the higher voltage input to source output. The comparator threshold is the voltage difference needed between both inputs (IN1, IN2) to switch to the higher input supply voltage. When the device selects the input, the switch is on for at least the latch-off time. The switches can be manually controlled instead of auto-selected with the enable inputs.
The MAX14727/MAX14728/MAX14731 are path selectors with an overvoltage protection feature. The overvoltage threshold can be externally set with a voltage divider or the internal OVLO can be used. Between the two inputs, INA has priority. INB takes over INA either when INB is the only present input or when INB is valid (above 4.1V, typical) and INA is invalid (below 4.1V, typical). The devices also have an OTG feature so output can supply input(s).
The MAX14740/MAX14741/MAX14742/MAX20320 power path selectors auto-select the higher input voltage and also have manual reset inputs (MR) to reset, disconnect, or connect the switches. The MAX14740 has an I2C interface and most of the parameters are programmable. The MAX14741/MAX14742/MAX20320 have a GPIO interface, and there are two comparator thresholds available to be chosen. The switches can still be manually controlled instead of auto-selected with the enable inputs, and both switches can be manually turned on at the same time.
Device | Comparator Threshold | Input Absolute Max | Internal OVLO | Soft Start Output Limit (100µF Load) | Automatic Switch Latch-Of | Communication |
MAX14713 | 200mV | 6V | - | 15mV/µs | Yes (85ms typical) | GPIO |
MAX14714 | 500mV | 6V | - | 60mV/µs | No | GPIO |
MAX14727 | - | 30V | 13.75V | 10mV/µs | No | GPIO |
MAX14728 | - | 30V | 10V | 10mV/µs | No | GPIO |
MAX14731 | - | 30V | 5.92V | 10mV/µs | No | GPIO |
MAX14740 | Programmable | 6V | - | 20mV/µs or 60mV/µs | Yes (programmable) | I2C |
MAX14741 | 300mV/500mV | 6V | - | 60mV/µs | No | GPIO |
MAX14742 | 200mV/400mV | 6V | - | 60mV/µs | No | GPIO |
MAX20320 | 200mV/400mV | 6V | - | 60mV/µs | No | GPIO |