Fan controller
Fan controller ( 1 ) for a modular power supply having a fan ( 13 ). An output ( 8 ) is provided for transmitting control signals to the fan ( 13 ) for controlling fan speed. A plurality of sensor modules ( 20 ) are associated with a respective module ( 11, 6, 7 ) of the modular power supply. Each sensor module ( 20 ) includes a temperature detecting circuit comprising a sensor for sensing temperature variations in the respective module ( 11, 6, 7 ), a fan control circuit ( 30 ) galvanically isolated from the temperature detecting circuit for outputting a control signal to the output ( 8 ) for controlling the fan ( 13 ), and an optocoupler ( 10,9 ) for transferring an output signal from the temperature detecting circuit ( 20 ) to the fan control circuit ( 30 ) for generating the control signal.
1. A fan controller for a modular power supply having a mains input side, a low voltage output side comprising a plurality of galvanically isolated output modules, and a fan, the fan controller comprising:
an output for transmitting control signals to the fan for controlling fan speed; and
a plurality of sensor modules each sensor module associated with a respective one of the plurality of output modules of the modular power supply, wherein each sensor module comprises:
a temperature detecting circuit comprising a sensor for sensing temperature variations in the respective module;
a fan control circuit galvanically isolated from the temperature detecting circuit for outputting a control signal to the output for controlling the fan; and
an optocoupler for transferring an output signal from the temperature detecting circuit to the fan control circuit for generating the control signal.
2. The fan controller according to claim 1 , wherein the temperature detecting circuit comprises an operational amplifier for generating the output signal.
3. The fan controller according to claim 2 , wherein the operational amplifier is configured as a bridge.
4. The fan controller according to claim 2 , wherein the operational amplifier comprises negative feedback.
5. The fan controller according to claim 1 , wherein the temperature detecting circuit has a set-point corresponding to an activation temperature and generates the output signal when the temperature sensed by the sensor exceeds the activation temperature.
6. The fan controller according to claim 1 , wherein the sensor is a thermistor.
7. The fan controller according to claim 1 , wherein the optocoupler comprises a light-emitting component connected to the temperature detecting circuit and a light detecting component connected to the fan control circuit.
8. The fan controller according to claim 7 , wherein the light-emitting component is a light-emitting diode.
9. The fan controller according to claim 7 , wherein the light detecting component is a photodiode or a phototransistor.
10. The fan controller according to claim 1 , wherein the fan control circuits of the plurality of sensor modules are connected to the output in a wired OR arrangement.
11. The fan controller according to claim 1 , wherein, in use, the output transmits the sum of the control signals from the plurality of sensor modules to the fan for controlling fan speed.
12. The fan controller according to claim 1 , wherein the output comprises a digital filter for filtering the control signals transmitted to the fan.
13. The fan controller according to claim 12 , wherein the digital filter has a pole at 0.01 Hz.
14. The fan controller according to claim 1 , wherein the output comprises a low pass filter for filtering the control signals transmitted to the fan.
15. A power supply comprising:
a mains input side;
a low voltage output side comprising a plurality of output modules;
a fan for cooling the plurality of modules, the fan having an input for receiving a control signal for controlling the fan's speed; and
a plurality of sensor modules, each sensor module associated with a respective output module of the plurality of output modules of the modular power supply, wherein each sensor module comprises:
a temperature detecting circuit comprising a sensor for sensing temperature variations in the respective module;
a fan control circuit galvanically isolated from the temperature detecting circuit for outputting a control signal to the fan's input for controlling the fan; and
an optocoupler for transferring an output signal from the temperature detecting circuit to the fan control circuit for generating the control signal.