Tool/software:
Hello,
After reading APP Note SLVA948 I bought the EVM Kit for the TPS2595 as well for the TPS24750.
The goal was to have a directional switch to connect or disconnect a Li-Ion Battery to the charger. Application is a handheld device with external power input and charging option.
Depending on the battery ( rechargeable or non-rechargeable):
- In case of non recharging I wanted ensure that there was no connection between the battery and the charger.
- In case of recharging I wanted to have a direct connection between battery and charger. Moreover, the current should be allowed to flow in both directions. Recharging, and in case of powering the system. Current flowing from the battery to the system.
After some tests I noticed that a strange behavior happens on both TPS2595 as well as on the TPS2475X, one that I cannot explain and I would like clarification and help to understand it. Perhaps I am doing something wrong?
When just using 1 single device testing ENabling and disabling:
- Power supply 2.8V@A
- Load OFF
- J5 Open
- Output Voltage 2.8V
Comment: So far everything fine.
- Power Supply 2.8V@2A
- Load Set 1.82A
- J5 Open
- Output Voltage 2.5V
Comments: Everything fine. 0.3 V drop on the cables. For testing ok.
- Power Supply 2.8V@2A
- Load Set 1.82A
- J5 Closed
- Output Voltage ~0V
Comments: When I pull down EN the Efuse disconnects the output from the input. OK. Everything fine.
- Power Supply 2.8V@2A
- Load Set 1.82A
- J5 Open
- Output Voltage 18mV
Comments: It is when I open the J5 again that this strange behavior happens. Instead of reestablish connection again between output and input, the device keeps delivering this 0.681A to the load but with a very little voltage.
What could be happening here? It looks like the Efuse gets into a unknown state.
BR,
Nelson
