4 ms·
If the total power consumption at the supply is the same or lower, how is the voltage regulation circuitry generating more heat?
by jhenkens 3y ago
If the total power consumption at the supply is the same or lower, how is the voltage regulation circuitry generating more heat?
- mschuster91 3y agoThe problem is the voltage drop. The bigger voltage difference it has to handle, the hotter it gets as its the loss from "internal loss current x voltage drop" is converted into hat.
- jhenkens 3y agoThe heat has to come from the input power though. If I'm pumping 5W at 12V, or 5W at 20V into the device, with it idling, presumably the output from the devices voltage regulator circuit is the same voltage, and the downstream components are consuming the same wattage (let's call it 1A at 3.3V downstream, so 3.3W), the both the 12V and the 20V input would have 1.7W of heat-loss. The article shows that as voltage goes up, power actually drops, which would imply that it is producing less heat.
- onetwentythree 3y agoThat only applies to linear regulators. The router on this page uses a switching regulator. Switching regulators have a relatively constant power draw over the entire input voltage range.
- tonyarkles 3y agoYeah, I think they’ve mixed up linear regulators and buck converters. Buck converters are often more efficient with a larger voltage drop because the switch can run with a lower duty cycle.
- jhenkens 3y agoThanks, I never knew why. All I knew is whenever I need a buck converter in my DIY, novice PCBs, I just toss in an off-the-shelf preassembled one, with a small LDO on my actual PCB to drop the last bit and smooth it out.