Hi, I have a circuit with a ucontroller (16F1825) which controls a well known sd-card amplifier known as a DF player.
The battery supply is 4.2v max (li-ion battery) and at that voltage the DF player doesn't work well, if at all, despite the specs suggesting otherwise., and I have tried a few!
I added a small boost converter to boost the voltage to 5v for the DF player, and with this it works well.
So, controller is at battery voltage, DF player at 5v. I used a IRL540 to power the DF player on/off, as the standby current was unacceptable even when in sleep. Everything worked well on a breadboard. Now I have put it all on stripboard I am struggling to saturate the Fet I think, and I do not know why... well, I think I have an idea, but I am surprised it worked well on an old breadboard but not on stripboard! When I say saturate, when I measure the ground of the dfmodule switched on the meter is reading maybe 25mV above ground, so suspect noise is the issue between ground and data, perhaps from the boost reg.
I find that in order for the DFplayer to be turned on, the pic isn't quite saturating the transistor enough even at 4.2V. If I remove the output pin of the pic and connect the gate to +V the dfplayer is then able to respond to the pics comm request and turn on.. But with the meter, I am not measuring any significant difference between the pic pin and going straight to the supply.
Iknow switching the ground is not ideal, but not sure what else to try tbh! I have no P fets to try, and to be honest they never work as well as N-type in low side switching, I would rather not add to the circuit but realize I might have to?
The circuit has to be able to go in to standby with minimal current consumption this is why I want to switch the sound module.
Can someone please give me some guidance as to how I can reliably switch the sound module on/off with the difference in voltages between pic and dfmodule please?
The battery supply is 4.2v max (li-ion battery) and at that voltage the DF player doesn't work well, if at all, despite the specs suggesting otherwise., and I have tried a few!
I added a small boost converter to boost the voltage to 5v for the DF player, and with this it works well.
So, controller is at battery voltage, DF player at 5v. I used a IRL540 to power the DF player on/off, as the standby current was unacceptable even when in sleep. Everything worked well on a breadboard. Now I have put it all on stripboard I am struggling to saturate the Fet I think, and I do not know why... well, I think I have an idea, but I am surprised it worked well on an old breadboard but not on stripboard! When I say saturate, when I measure the ground of the dfmodule switched on the meter is reading maybe 25mV above ground, so suspect noise is the issue between ground and data, perhaps from the boost reg.
I find that in order for the DFplayer to be turned on, the pic isn't quite saturating the transistor enough even at 4.2V. If I remove the output pin of the pic and connect the gate to +V the dfplayer is then able to respond to the pics comm request and turn on.. But with the meter, I am not measuring any significant difference between the pic pin and going straight to the supply.
Iknow switching the ground is not ideal, but not sure what else to try tbh! I have no P fets to try, and to be honest they never work as well as N-type in low side switching, I would rather not add to the circuit but realize I might have to?
The circuit has to be able to go in to standby with minimal current consumption this is why I want to switch the sound module.
Can someone please give me some guidance as to how I can reliably switch the sound module on/off with the difference in voltages between pic and dfmodule please?