Abstract: A time-multiplexed thermal sensing circuit is provided for control and sensing of two thermistors over a single line electrical coupling. The circuit may include a first diode that selectively couples or isolates a first thermistor from a sense node based on the polarity of an applied voltage to the sense node. The circuit may further include a second diode that selectively couples or isolates a second thermistor from the sense node based on the polarity of the applied voltage to the sense node such that only of the thermistors is coupled to the sense node at any time.

Abstract: A time-multiplexed thermal sensing circuit is provided for control and sensing of two thermistors over a single line electrical coupling. The circuit may include a first diode that selectively couples or isolates a first thermistor from a sense node based on the polarity of an applied voltage to the sense node. The circuit may further include a second diode that selectively couples or isolates a second thermistor from the sense node based on the polarity of the applied voltage to the sense node such that only of the thermistors is coupled to the sense node at any time.

Abstract: An electronic housing assembly is formed with an environmental seal (20), EMI control (56) and a good thermal coupling (44, 46) made between enclosed hot electric components (48, 50) and an exterior heat sink (52, 54).

Abstract: A control circuit used in a lamp system. The lamp system has a first and a second light emitting diode (LED) connected together in series. The control circuit includes a current source for connecting to the first LED to provide a regulated drive current to the first and second LEDs in order to illuminate the LEDs. The control circuit includes a switching component for connecting in parallel with the first LED to divert the driver current from the first LED and provide the driver current to the second LED when the switching component is activated. The control circuit includes a controller for selectively activating the switching component in order to selectively extinguish the first LED.

Abstract: A device used with a direct current power source for energizing a lamp. The device includes a plurality of input channels selectively connected to the power source for providing current to the lamp. For each input channel, the device includes a corresponding current sensing component connected to the input channel, and a corresponding bypass switch connected in parallel with the current sensing component. Each current sensing component produces a measurable signal as a function of current that is provided by the corresponding input channel. The device includes a controller connected to the current sensing components and the bypass switches. The controller identifies the input channel that is providing current to the lamp as a function of the measurable signals and controls the bypass switches based on the identified input channel.

Abstract: An electronic housing assembly is formed with an environmental seal (20), EMI control (56) and a good thermal coupling (44, 46) made between enclosed hot electric components (48, 50) and an exterior heat sink (52, 54).

Abstract: A control circuit used in a lamp system. The lamp system has a first and a second light emitting diode (LED) connected together in series. The control circuit includes a current source for connecting to the first LED to provide a regulated drive current to the first and second LEDs in order to illuminate the LEDs. The control circuit includes a switching component for connecting in parallel with the first LED to divert the driver current from the first LED and provide the driver current to the second LED when the switching component is activated. The control circuit includes a controller for selectively activating the switching component in order to selectively extinguish the first LED.

Abstract: A device used with a direct current power source for energizing a lamp. The device includes a plurality of input channels selectively connected to the power source for providing current to the lamp. For each input channel, the device includes a corresponding current sensing component connected to the input channel, and a corresponding bypass switch connected in parallel with the current sensing component. Each current sensing component produces a measurable signal as a function of current that is provided by the corresponding input channel. The device includes a controller connected to the current sensing components and the bypass switches. The controller identifies the input channel that is providing current to the lamp as a function of the measurable signals and controls the bypass switches based on the identified input channel.

Abstract: A temperature sensing circuit for a ballast for a HID lamp multiplexes the temperature measurement function with another function to reduce the number of pins required for the temperature measurement function performed by the microcontroller of the ballast. The circuit includes a microcontroller having a first A/D input/output pin, a second A/D input/output pin and a multifunction pin, a temperature measurement circuit connected to the second A/D pin, a timing circuit connected to the first A/D pin, and a switch connected to the multifunction pin, temperature measurement circuit and timing circuit. The switch activates the temperature measurement function by connecting the temperature measurement circuit to the multifunction pin in a first position and deactivates the function by disconnecting the temperature measurement circuit from the multifunction pin in a second position.

Abstract: A high intensity discharge (HID) assembly comprises ballast circuits which includes a micro-controller, and an HID headlamp. In order to deter theft of the HID assembly from a vehicle, the micro-controller communicates with a vehicle computer, checks the VIN of the vehicle, and if the micro-controller does not recognize the VIN, causes the HID headlamp to operate in a flickering power output mode. The ballast circuits include a power control circuit, a lamp current regulator, a 400v regulator, a current sense circuit, a turn-on synchronization circuit, a shut down circuit, and a pulse width modulator.

Abstract: A circuit for operating a high intensity discharge (HID) lamp includes an H-bridge connected between a common terminal and a power line, and a control circuit connected to the H-bridge. The control circuit includes a transformer having a primary winding connected between the common terminal and a power terminal and a secondary winding connected between the common terminal and the power line, and a current sense resistor connected in series between the secondary winding and the common terminal. The HID lamp is connected to the common terminal and to the second winding so as sense a current across the current sense resistor.

Abstract: A circuit for operating a high intensity discharge (HID) lamp includes an H-bridge connected between a common terminal and a power line, and a control circuit connected to the H-bridge. A boost circuit is connected in parallel with the H-bridge between the power line and the common terminal, where the boost circuit includes a resistor, a Zener diode and a capacitor connected in series.