O2 Micro, Incorporated

O2micro International Limited

02 Micro International Limited

02micro Inc.

O2mincro, Inc.

Xiaohu Tang

Guoxing Li

Wei Wang

XiaoHua Hou

Weidong Xue

Yan Li

Anquan Xiao

Shiqiang Liu

Xiaofei Gong

A battery management system includes detecting circuitry and control circuitry coupled to the detecting circuitry. The detecting circuitry detects cell voltages of battery cells of a battery pack. The control circuitry alternates between a normal state and a charging prohibition state. In the normal state, charging of the battery cells is enabled and the cell voltages increase, and if a voltage of a battery cell of the battery cells exceeds a predetermined overcharge threshold, then the control circuitry transitions to the charging prohibition state. In the charging prohibition state, charging of the battery cells is disabled, and the voltage of the battery cell decreases if at least one cell of the battery cells has a voltage less than a balance threshold. If the voltage of the battery cell falls to a predetermined overcharge-released threshold, then the control circuitry transitions to the normal state and enables charging of the battery cells.

Battery management system

A circuit measures a cell voltage of a cell in a battery. The circuit includes a measurement circuit and a current generator. The measurement circuit includes a first terminal coupled to a positive terminal of a cell via a first resistive element and includes a second terminal coupled to a negative terminal of the cell via a second resistive element. The measurement circuit consumes a first current. The current generator generates a first compensation current according to the first current. The first current and the first compensation current flow from the positive terminal through the first resistive element to the first terminal. The measurement circuit calculates the cell voltage according to a first voltage difference between the first and second terminals when the first compensation current is disabled and according to a second voltage difference between the first and second terminals when the first compensation current is enabled.

Circuits and methods for measuring a cell voltage in a battery

An operational amplifier with different power supply voltages includes an input stage and an output stage. The input stage includes a current source for providing a bias current, and a differential input circuit for receiving the bias current and differential input voltage signals, and converting the differential input voltage signal to differential input currents. The input stage is supplied by a first power supply voltage. The output stage includes a load circuit coupled to the differential input voltage signal and for receiving the differential input currents, and outputting a single ended output voltage signal. The output stage is supplied by a second power supply voltage. The second power supply voltage is lower than the first power supply voltage.

Operational amplifier with different power supply voltages

A temperature detection circuit includes a sensor, an integrated circuit (IC) chip, and a resistor. The sensor is operable for sensing a temperature. The IC chip can compare a sense voltage indicative of the temperature with a threshold voltage indicative of a temperature threshold to determine a temperature condition. The IC chip has a substantially constant parameter. The resistor is externally coupled to the IC chip. The IC chip maintains a current ratio, including a ratio of a first current flowing through the sensor to a second current flowing through the resistor, equal to the substantially constant parameter.

Circuits and methods for temperature detection

A circuit for detecting an input voltage includes a voltage-to-current converter and a current comparator. The voltage-to-current converter is operable for generating a monitoring current that varies in accordance with the input voltage. The current comparator coupled to the voltage-to-current converter is operable for comparing the monitoring current to a threshold current proportional to the temperature of the circuit, and for generating a detection signal indicating a condition of the input voltage based on a result of the comparison.

Circuits and methods for voltage detection

A conversion system includes a conversion circuit coupled to multiple cells for generating multiple sampling signals indicative of the cell voltages of the cells respectively. Each sampling signal is with respect to the same reference level. In addition, the conversion system includes a compensation circuit coupled to the conversion circuit for generating a compensation current that flows through at least one cell of the multiple cells via the conversion circuit for balancing the currents respectively flowing through the cells.

Conversion systems with balanced cell currents

The present invention is a LDO voltage regulator circuit with common-mode feedback. The LDO voltage regulator includes an error amplifier with a common-mode feedback unit, a pass device and a compensation circuit. A signal from the pass device acts as an input signal to the error amplifier and is compared with another input signal, producing a differential signal. The differential signal is amplified and then provided to the pass device. A capacitor in the compensation unit provides frequency compensation to the LDO voltage regulator. The common-mode feedback unit incorporated into the error amplifier greatly improves a slew rate of a gate voltage of the pass device.

Low drop-out voltage regulator with common-mode feedback

The present invention is a voltage regulator circuit with enhanced frequency compensation. The voltage regulator includes an error amplifier, a dynamic bias circuit, an enhanced frequency compensation unit, a pass device and a compensation circuit. A signal from the pass device acts as an input signal of the error amplifier and is compared with another input signal, producing a differential signal. The differential signal is amplified and then provided to the dynamic circuit and the enhanced frequency compensation unit. The enhanced frequency compensation unit is provided such that a zero reference value in a left-hand plane can be generated to optimize the compensation for the voltage regulator circuit. The error amplifier includes a capacitor for compensating an output voltage of the voltage regulator circuit.

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Shanghai, China

Xiaohu Tang