US 7,592,777 B2
Current mode battery charger controller
Chun Lu, San Jose, Calif. (US); You-Yuh Shyr, San Jose, Calif. (US); Alexandru Hartular, San Jose, Calif. (US); and Constantin Bucur, Santa Clara, Calif. (US)
Assigned to O2Micro International Limited, Georgetown, Grand Cayman (Cayman Islands)
Filed on Nov. 18, 2005, as Appl. No. 11/283,087.
Claims priority of provisional application 60/671754, filed on Apr. 15, 2005.
Prior Publication US 2006/0232241 A1, Oct. 19, 2006
Int. Cl. H02J 7/16 (2006.01)
U.S. Cl. 320—141  [320/134; 320/162] 8 Claims
OG exemplary drawing
 
1. An integrated circuit (IC) for controlling a DC to DC converter, said (IC) comprising:
a current source configured to generate a current source signal, said current source signal is received at a common node;
a first error amplifier configured to compare a first signal representative of a charging current provided to a rechargeable battery with a maximum charging current and provide a current control signal received at said common node in response to said comparison;
an internal compensation network, internal to said IC, comprising a compensation capacitor coupled in series with a compensation resistor, said internal compensation network is coupled to said common node; wherein said current source is configured to charge said compensation capacitor an generate a compensation signal at said common node, said compensation signal is proportional to the voltage of said compensation capacitor; and wherein, if said first signal representative of a charging current provided to a rechargeable battery exceeds said maximum charging current, said current control signal sinks said current source signal and reduces said compensation signal; and
a comparator configured to compare an inductor current signal representative of an inductor current through an inductor of said DC to DC converter with said compensation signal, wherein a reduction in said compensation signal results in a control signal provided by said current mode battery charger controller to reduce a charging current from said DC to DC controller.