Patent ID: 8629660

Claim:
A boost regulator circuit comprising: an inductor having a first inductor connection to a voltage input and a second inductor connection to a switching node; a switching transistor having a drain (collector) connected to the switching node, a source (emitter) electrically connected to ground directly or through a sense resistor, and a gate (base); a diode having an anode connected to the switching node and a cathode connected to an output node; a plurality of light emitting diodes electrically connected in series to the output node; a dimming transistor electrically connected between ground and at least one of the plurality of light emitting diodes; a capacitor/resistor voltage divider connected between the switching node and ground, the capacitor/resistor voltage divider including a first capacitor/resistor pair and a second capacitor/resistor pair, the first capacitor/resistor pair connected in parallel between the switching node and a near switching node and the second capacitor/resistor pair connected in parallel between the near switching node and the source (emitter) of the switching transistor; and a light emitting diode control circuit, the light emitting diode control circuit including a control circuit having a first input directly connected to the near switching node and a switching signal output connected to the gate (base), the control circuit configured to provide a switching signal, at the switching signal output, to the gate (base) when a near switching node potential at the near switching node is at least substantially near a ground potential and a current through the inductor is at least substantially near zero to cause the switching transistor to transition from an off state to an on state, the light emitting diode control circuit electrically connected to the dimming transistor and configured to cause the dimming transistor to oscillate between an on state and an off state to control a current through the plurality of light emitting diodes, the light emitting diode control circuit controlled by a backlight control system.