Silicon Laboratories Inc.

Jia-Hau Liu

Alan Lee Westwick

Douglas S Piasecki

Thomas Saroshan David

Dazhi Wei

Timothy Thomas Rueger

Stefan N Mastovich

Xiaoling Guo

An LCD controller includes a charge pump for generating a charge voltage responsive to an external voltage and a clock signal. The controller further includes an oscillator for generating the clock signal responsive to an oscillator control signal. An LCD driver voltage circuit generates a plurality of LCD driver voltages for driving segments of an associated LCD display. A loop control circuit within the LCD controller monitors an LCD driver voltage from the LCD driver voltage circuit and generates the oscillator control signal responsive thereto to enable and disable the oscillator.

System and method for LCD loop control

An LCD controller includes a charge pump circuit for generating a charge voltage responsive to an external voltage and a clock signal. An oscillator generates the clock signal responsive to at least one bias voltage. The oscillator has a high power mode of operation and a low power mode of operation. Bias circuitry for applies the at least one bias voltage to the oscillator. The at least one bias voltage is applied to the oscillator from an external source in the high power mode of operation and the at least one bias voltage is applied to the oscillator from a source within the oscillator in the low power mode of operation. An LCD driver voltage circuit generates a plurality of LCD driver voltages for driving segments of an LCD display responsive to the charge voltage.

LCD controller with oscillator prebias control

The single chip microcontroller unit includes a processing unit having normal power mode of operation and a low power mode of operation. Analog circuitry and digital circuitry are connected to the processing unit. Monitoring circuitry determines if a chip supply voltage level exceeds a threshold level necessary to maintain operation of the digital circuitry.

Microcontroller unit having power supply voltage monitor

The single chip microcontroller unit includes a processing unit having normal power mode of operation and a low power mode of operation. Analog circuitry and digital circuitry are connected to the processing unit. A power management unit controls power operations of the processing unit, the analog circuitry and the digital circuitry. Power monitoring circuitry provides power control signals to the power management unit. The power monitoring circuitry further includes a system voltage monitoring circuit for generating a system voltage control signal responsive to a system voltage level with respect to a predetermined level. The power monitoring circuitry also includes a supply monitoring circuit for determining if a chip supply voltage level exceeds a threshold level.

System for monitoring power supply voltage

An apparatus comprises a band gap voltage generator circuit for generating a band gap voltage. A temperature invariant current generator is located within the band gap voltage generator circuit for generating a temperature invariant current. A temperature invariant current correction circuit is located within the band gap voltage generator circuit and adjusts the output voltage responsive to the temperature invariant current without altering temperature characteristics of the temperature invariant current.

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Austin, TX, United States of America

Jia-Hau Liu