Over-voltage protection for power and data applications
View Patent ↗A power supply device is described comprising a DC voltage supply, a power section connected to the DC supply for supplying DC power from the DC voltage supply to first and second outlet ports for connection to a remote device via a cable connection, a voltage boosting circuit for generating a voltage above that of the DC supply, an energy absorbing circuit connected between an output of the voltage boosting circuit and a ground potential, and a diode connection means between the first outlet port and the energy absorbing circuit. The major components of the power supply device may be implemented as an integrated circuit.
1. A method of operating a power supply device, comprising:
supplying DC power at a first DC voltage to first and second outlet ports of the power supply device,
generating, using a DC voltage supply, a second DC voltage equal to, or greater than, the first DC voltage, wherein the second DC voltage is supplied to an energy absorbing circuit,
diverting current from the first outlet port to the energy absorbing circuit if an instantaneous voltage at the first outlet port exceeds the second DC voltage, and
absorbing energy from the current in the energy absorbing circuit.
2. A power supply device, comprising:
first and second DC voltage supply input ports, wherein, when coupled to a first DC voltage supply, the first DC voltage supply input port has a first DC voltage;
first and second outlet ports, wherein the first DC voltage supply input port is coupled to the first outlet port;
a power section coupled between the second DC voltage supply input port and the second outlet port;
a second DC voltage supply providing during operation a second DC voltage at least equal to the first DC voltage;
an energy absorbing circuit output port coupled to the second DC voltage supply; and
a diode having an anode coupled to the first outlet port, and a cathode coupled to the second DC voltage supply, wherein the diode is configured to divert current from the first outlet port to the energy absorbing circuit.
3. The power supply device according to claim 1 , further comprising a voltage boosting circuit configured to generate the second DC voltage.
4. The power supply device of claim 1 , further comprising a mixed signal control section coupled to the power section.
5. The power supply device of claim 1 , wherein the power section includes a power switch coupled to the second DC voltage supply input port, and a current sensing device configured to sense through the power switch.
6. The power supply device of claim 5 , further comprising a second diode coupled in parallel with the power switch, having an anode coupled to the current sensing device and a cathode coupled to the second outlet port.
7. The power supply device of claim 5 , further comprising a capacitor coupled between a switch control terminal of the power switch and the second outlet port.
8. The power supply device of claim 5 , wherein the power switch is configured to control the amount of current supplied to toy the first and second outlet ports based on an output from the current sensing device.
9. The power supply device of claim 1 , further comprising a second diode coupled between the first outlet port and ground.
10. The power supply device of claim 1 , further comprising a second diode coupled between the output of the second DC voltage supply and the second outlet port.
11. The power supply device of claim 2 , further comprising a second diode having an anode coupled to the second DC voltage supply input port and a cathode coupled to the first outlet port.
12. A network component comprising the power supply device according to claim 1 .
13. The power supply device of claim 1 , further comprising:
a first DC voltage supply coupled to the first and second DC voltage supply input ports; and
an energy absorbing circuit coupled between ground and the energy absorbing circuit output port.
14. The power supply device of claim 13 , wherein the energy absorbing circuit includes a shorter term energy absorbing device and a longer term energy absorbing device.
15. The power supply device of claim 14 , wherein at least one of the shorter term energy absorbing device and the longer term energy absorbing device includes a capacitor.
16. The power supply device of claim 15 , wherein the shorter term energy absorbing device includes a first capacitor and the longer term absorbing device includes a second capacitor, and the first and second capacitors are coupled in parallel.