Well, initial testing is done. This one makes 24.009 volts at the output with nothing plugged into the Fan Control header. Once loaded to 70 watts, it still makes the same with 9.6mV of ripple. The ripple decreases at lower loads. At that point, my input is at 11.7 volts. The inductor gets to about 96degC at the full 70 watt load. It's rated to 125degC. These tiny Carbonyl Iron inductors are amazing. This one is 6mm square and takes up 1/4 of the space that the prior board version used.
Once I try to crawl past 72 watts on the load, the IQDSM starts to dial back the voltage to maintain the operating point. This is the input current limit kicking in.
The Green LED is only run at about 1/2 normal power and I used a diffused lens so it's not very obtrusive. But it doesn't go out until the voltage is down by at least 9% from the target when the current limit is in effect. I suppose that'll have to do.
I probably need to dial back the snubber capacitors a bit. The switch node ring on the output side is lower in amplitude compared to the prior version and over-snubbing wastes power. I err on the side of bigger when designing so I don't destroy the FETs when first testing. Once I recalculate the snubbers, I'll be good to make the other test boards.
Tomorrow I'll hook up a PWM test tool and check the control characteristics and the ring on the input switch node at the lower output voltages (< 12V).
Eventually, of course, I'm going to have run a D5 Strong with it using the bucket of water test rig.![Smile](https://forum.dazmode.com/core/images/smilies/happy0163.gif)
Now though ... I have to go watch football.
Once I try to crawl past 72 watts on the load, the IQDSM starts to dial back the voltage to maintain the operating point. This is the input current limit kicking in.
The Green LED is only run at about 1/2 normal power and I used a diffused lens so it's not very obtrusive. But it doesn't go out until the voltage is down by at least 9% from the target when the current limit is in effect. I suppose that'll have to do.
I probably need to dial back the snubber capacitors a bit. The switch node ring on the output side is lower in amplitude compared to the prior version and over-snubbing wastes power. I err on the side of bigger when designing so I don't destroy the FETs when first testing. Once I recalculate the snubbers, I'll be good to make the other test boards.
Tomorrow I'll hook up a PWM test tool and check the control characteristics and the ring on the input switch node at the lower output voltages (< 12V).
Eventually, of course, I'm going to have run a D5 Strong with it using the bucket of water test rig.
![Smile](https://forum.dazmode.com/core/images/smilies/happy0163.gif)
Now though ... I have to go watch football.
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