iPSU V6.0 - is a complete power supply unit for stereo audio amplifier. Version V6.0 includes fallowing features:
- Auxilary +/-15V @ 100mA power supply (short circuit/over load protected)
- MOSFET SSR relay
- 2x Thermal protecion
- 2x DC protection (TRIGGER LEVEL 1,2VDC)
- Delayed speakers ON (5s delay) - reduces speakers ''thumb'' at amplifier turning ON phase
- Fast speakers OFF - after main transformer AC is switched off SSR relay is switched OFF so the speakers are disconnected
- Short circuit and overload protection (TRIGGER LEVEL 10A)
Main reservoir capacitors are separated with small value/high power resistors at the bottom of the PCB. There are two advantages of this kind of setup, first one is lover harmonics at PSU rails and second is safety. In case of short circuit the SMD resistors are popping out/blowing like a fuses, those resistors saved my circuits many times. Protection circuit is using Schmitt trigger as a comparator, it provides fast transient response and adds hysteresis required for temperature protection. DC protection triggers at 1,2VDC on the amplifier output. iPSU is designed for 2x 30Vac to 2x 40Vac transformers (I have tested also 2x 45Vac transformers and works OK). For lower voltage transformers two resistors must be tweaked to provide stable 24VDC supply for the protection circuity. Temperature is sensed with two 100kR thermistors which are placed at the amplifier heat-sinks. Temperature protection is latched at approx 13VDC on the thermistor/resistor divider and released at 16VDC so some adjustment may be required.
To make it a bit more clear please watch the video bellow. (I will update EN version of the video later on).
Some very old EN video version bellow