Other Parts Discussed in Thread: TPS40170,
Hello,
We are developing a low noise output DC-DC converter using the TPS40170 and have developed a prototype based on the TPS40170EVM-597.
We have achieved low noise (less than 5 mV pp) by post filtering the switching ripple and noise, frequency locking to a crystal based external oscillator and providing a low noise external reference.
The dominant noise now has a 1/f characteristic with frequency components less than 15 kHz.
We believe the dominant noise source is now the input noise of the TPS40170 internal error amplifier.
Can you provide any data on the input noise of the TPS40170 internal error amplifier?
Can you please advise on the effect of bypassing the internal error amplifier and of driving the COMP pin from a low impedance output external error amplifier might be?
If the error amplifier inverting input is left floating can we force the output of the amplifier (the COMP) pin using an external error amplifier?
Do you have any noise data or recommendations for low noise operation for the TPS40170 oscillator and TPS40170 PWM comparator ?
Do you have any recommendations for an alternative DC-DC controller to realise a low noise output.
Our requirement is 24 V DC in to 5 V / 8 A out and 24 V DC in to 12 V / 2 A out
Regards
Peter Sykes
