Patent ID: 7830115

Claim:
A cradle charging system, comprising: a charging cradle defining a space for receiving a battery of an electronic device; a transformer charging circuitry for charging the battery in the electronic device, the transformer charging circuitry further comprising: primary side circuitry for receiving a charging voltage; secondary side circuitry for inductively coupling the charging voltage to the battery, wherein the secondary side circuitry provides a controlled output signal based on either constant voltage control or constant current control responsive to a charge level of the battery, wherein the secondary side circuitry has a negative voltage for a ground reference, wherein the secondary side circuitry has a negative voltage for a ground reference; and a control circuit for generating the controlled output signal responsive to at least one of a sensed charging voltage to the battery and a sensed charging current to the battery, wherein the control circuit generates a voltage control signal as the controlled output signal responsive to the sensed charging voltage and a reference voltage in a first mode of operation and wherein the control circuit generates a current control signal as the controlled output signal responsive to the sensed charging current and the reference voltage in a second mode of operation.