Combined LDO regulator and battery charger

A circuit for charging a battery and providing a supply voltage to a load, comprising:

• a low-drop-out (LDO) regulator that is arranged to couple to a power source, the LDO regulator comprising:
• a power pass device that is coupled to the power source and the load;
• and
• an LDO control loop that is coupled to the power pass device;
• and
• a constant current, constant voltage (CC-CV) current regulator that is coupled to the LDO regulator, the CC-CV current regulator comprising:
• a current sense device that is coupled to the power pass device of the LDO regulator;
• a voltage sense integrator that is coupled to the battery and the current sense device;
• and
• a current source that is coupled to the voltage sense integrator and the LDO control loop of the LDO regulator, wherein the LDO voltage regulator and the CC-CV current regulator are arranged such that the supply voltage to the load and a charging current to the battery are simultaneously provided during a constant current mode, and wherein the supply voltage to the load and the charging current to the battery are provided on separate signals.

A constant current, constant voltage (CC-CV) current regulator, comprising:

• a current sense device that is arranged to sense a load current;
• a voltage sense integrator that is arranged to provide a first voltage in response to a battery charge voltage and the sensed load current;
• a current source that is arranged to provide a battery charging current to a battery in response to the first voltage;
• and
• a voltage divider that is arranged provide a control voltage to at least an input node of a voltage regulator in response to a combination of a portion of the battery charge voltage and a voltage to the load that is based, in part, on the battery charging current, wherein the voltage divider comprises a resistor that couples the input node of the voltage regulator to the battery, wherein the CC-CV current regulator is arranged such that the charging current to the battery, during the constant current mode, can be provided while the voltage regulator is providing a regulated voltage to the load.

A method for charging a battery and providing a supply voltage to a load, comprising:

• receiving an input signal from a power source;
• providing a regulated output signal to the load and a regulated charging signal to the battery, wherein the regulated output signal and the regulated charging signal are simultaneously provided during a constant current mode;
• providing a control signal based, at least in part, on the regulated output signal and the control signal, wherein the control signal is determined by:
• providing a first signal based on sensing a current of the regulated output signal;
• providing a second signal based on sensing a voltage of the regulated charging signal;
• and
• combining the first signal and the second signal;
• and
• controlling the regulated signal based on the control signal and based on a separate feedback signal wherein the feedback signal is based at least in part on the regulated signal.

A circuit for charging a battery and providing a supply voltage to a load, comprising:

• a means for regulating an input power signal to provide a regulated output signal to a load;
• a means for providing a charging signal to a battery;
• a means for sensing a current of the regulated output signal;
• a means for amplifying the sensed current of the regulated output signal to provide a first control voltage;
• a means for sensing a voltage of the charging signal;
• a means for amplifying the sensed voltage of the charging signal to provide a second control voltage;
• a means for combining the first control voltage and the second control voltage to provide a third control voltage;
• a means for controlling the regulated output signal based, in part, on the third control voltage and a separate feedback signal, wherein the feedback signal is based, at least in part, on the regulated output signal;
• and
• a means for reducing the current of the charging signal based, in part, on a charging status of the battery, wherein the means for regulating the input power signal and the means for providing the charging signal are arranged such that the regulated output signal and the charging signal are simultaneously provided during a constant current mode, and wherein the regulated output signal and the charging signal are separate signals.