Gas-discharge lamp controller utilizing a novel reheating frequency generation mechanism
View Patent ↗A gas-discharge lamp controller utilizing a novel preheating frequency generation mechanism, including: a resistance sensing means, used to generate a sensed voltage when coupled to an external series resistor-capacitor network, the external series resistor-capacitor network being biased between a first supply voltage and a reference ground; a sample and hold circuit, used to generate a sampled voltage of the sensed voltage under the control of a latch signal; and a mapping circuit, used to generate a control voltage according to a function of the sampled voltage.
1. A gas-discharge lamp controller utilizing a novel preheating frequency generation mechanism, comprising:
a resistance sensing means, used to generate a sensed voltage when coupled to an external series resistor-capacitor network, said external series resistor-capacitor network being biased between a first supply voltage and a reference ground;
a sample and hold circuit, used to generate a sampled voltage of said sensed voltage under the control of a latch signal; and
a mapping circuit, used to generate a control voltage according to a function of said sampled voltage.
2. The gas-discharge lamp controller utilizing a novel preheating frequency generation mechanism as claim 1 , further comprising an oscillator, having a first control end and a second control end, wherein the oscillation frequency of said oscillator is determined according to the voltage at said first control end and the time constant of said external series resistor-capacitor network when said external series resistor-capacitor network is coupled to said second control end, and wherein said first control end is coupled to said control voltage when said gas-discharge lamp controller is in a preheating phase.
3. The gas-discharge lamp controller utilizing a novel preheating frequency generation mechanism as claim 2 , further comprising a multiplexing means, which comprises:
a first comparator, used to generate a switch signal according to a voltage comparison of a second supply voltage and a UVLO turn-on voltage, said second supply voltage being proportional to said first supply voltage; and
a switch, having a switch control end, an input end, a first output end, and a second output end, wherein said switch control end is coupled to said switch signal; said input end is coupled to said external series resistor-capacitor network; said first output end is coupled to said resistance sensing means; and said second output end is coupled to said second control end of said oscillator.
4. The gas-discharge lamp controller utilizing a novel preheating frequency control mechanism as claim 3 , further comprising a second comparator, used to generate said latch signal according to a voltage comparison of said second supply voltage and a threshold voltage, wherein said threshold voltage is lower than said UVLO turn-on voltage.
5. The gas-discharge lamp controller utilizing a novel preheating frequency control mechanism as claim 1 , wherein said mapping circuit comprises a multiplier.
6. The gas-discharge lamp controller utilizing a novel preheating frequency control mechanism as claim 1 , wherein said mapping circuit comprises a look-up table based waveform generation circuit.
7. The gas-discharge lamp controller utilizing a novel preheating frequency control mechanism as claim 1 , wherein said resistance sensing means comprises a resistor.
8. The gas-discharge lamp controller utilizing a novel preheating frequency control mechanism as claim 1 , wherein said resistance sensing means comprises a current source.
9. The gas-discharge lamp controller utilizing a novel preheating frequency control mechanism as claim 2 , wherein said oscillator comprises an astable vibrator.
10. A gas-discharge lamp controller utilizing a novel preheating frequency generation mechanism, comprising:
a resistance sensing means, used to generate a sensed voltage when coupled to an external series resistor-capacitor network, said external series resistor-capacitor network being biased between a first supply voltage and a reference ground;
a sample and hold circuit, used to generate a sampled voltage of said sensed voltage under the control of a latch signal;
a mapping circuit, used to generate a control voltage according to a function of said sampled voltage;
an oscillator, having a first control end and a second control end, wherein the oscillation frequency of said oscillator is determined according to the voltage at said first control end and the time constant of said external series resistor-capacitor network when said external series resistor-capacitor network is coupled to said second control end, and wherein said first control end is coupled to said control voltage when said gas-discharge lamp controller is in a preheating phase;
a first comparator, used to generate a switch signal according to a voltage comparison of a second supply voltage and a UVLO turn-on voltage, said second supply voltage being proportional to said first supply voltage;
a switch, having a switch control end, an input end, a first output end, and a second output end, wherein said switch control end is coupled to said switch signal, said input end is coupled to said external series resistor-capacitor network, said first output end is coupled to said resistance sensing means, and said second output end is coupled to said second control end of said oscillator; and
a second comparator, used to generate said latch signal according to a voltage comparison of said second supply voltage and a threshold voltage, wherein said threshold voltage is lower than said UVLO turn-on voltage.