Hello!
I've build a regulated, adjustable power supply. Unfortunately, there isn't much space left for the heat sink - it's too small. However i can stil mount a fan to help cooling. I got the fan, a small but very efficient and unfortunately very noisy. I decided to make a circuit to control the fan. The basic idea is to keep the fan off when forced cooling isn't neccessary, and to regulate the fan's rpms (thus the cooling) regarding to the power dissipating in the supply. This can be achieved with two circuits. The first one is a voltage controled pwm - i've done it, works fine. The second circuit is a multipyer. That one should multiply two (analog) voltages. The 1st (X) is the voltage drop on the regulator and the 2nd (Y) is (also a voltage) proportional to the current flowing trough the regulator. The second circuit would then give an output proportional to the dissipating power (P=X*Y). Any ideas? Is it possible to multiply two analogue signals and have an analogue output to drive the fan??
Thank you!
iggy
I've build a regulated, adjustable power supply. Unfortunately, there isn't much space left for the heat sink - it's too small. However i can stil mount a fan to help cooling. I got the fan, a small but very efficient and unfortunately very noisy. I decided to make a circuit to control the fan. The basic idea is to keep the fan off when forced cooling isn't neccessary, and to regulate the fan's rpms (thus the cooling) regarding to the power dissipating in the supply. This can be achieved with two circuits. The first one is a voltage controled pwm - i've done it, works fine. The second circuit is a multipyer. That one should multiply two (analog) voltages. The 1st (X) is the voltage drop on the regulator and the 2nd (Y) is (also a voltage) proportional to the current flowing trough the regulator. The second circuit would then give an output proportional to the dissipating power (P=X*Y). Any ideas? Is it possible to multiply two analogue signals and have an analogue output to drive the fan??
Thank you!
iggy