Power management topologies

• US 7,348,760 B2
• Filed: 03/30/2004
• Issued: 03/25/2008
• Est. Priority Date: 09/21/2000
• Status: Expired due to Term

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Bucur, Constantin, Niculae, Marian, Popescu-Stanesti, Vlad, Nees, Daryl
• Primary Examiner(s): Tso; Edward H.
• Application Number:
  US10/812,802
• Publication Number:
  US 20040178766A1
• Time in Patent Office: 1,456 Days
• Field of Search: 320/132, 320/134, 320/128, 320/122, 320/106, 307/43
• US Class Current: 320/132
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A wake up circuit according to one embodiment includes a comparison circuit and an output decision circuit. The comparison circuit may be adapted to receive a first signal representative of a charging current level provided to a battery via a path and a second signal representative of a predetermined wake up current level and to provide a comparison output signal in response to the first and second signal. The output decision circuit may be adapted to receive at least the comparison output signal and a selector signal from a selector circuit, the output decision circuit providing one of the comparison output signal and the selector signal to a switch to control a state of the switch, the switch coupled to the path.

Claims

1. A wake up circuit comprising:

a comparison circuit configured to receive a first signal representative of a charging current level provided to a battery via a path and a second programmable signal representative of a predetermined wake up current level and to provide a comparison output signal in response to said first and second signals; and

an output decision circuit configured to receive at least said comparison output signal and a selector signal from a selector circuit, said output decision circuit is configured to provide one of said comparison output signal or said selector signal to a switch to control the charging current level provided to said battery by controlling the state of said switch-coupled to said path;

wherein said comparison output signal comprises an analog signal, said switch responsive to said analog signal to enter an intermediate conduction state to provide a current level to said battery representative of said predetermined wake up current level; and

wherein said selector signal comprises a first state and a second state, said switch is responsive to said first state to enter a full conduction state and responsive to said second state to turn off said switch.

2. The wake up circuit of claim 1, wherein said analog signal comprises a voltage signal, said switch comprising a field effect transistor having a gate terminal receiving said voltage signal.

3. The wake up circuit of claim 1, wherein said output decision circuit is further configured to receive at least one additional input signal in addition to said comparison output signal and said selector signal, said at least one additional input signal being an enabling signal, said output decision circuit responsive to said enabling signal to provide said comparison output signal to said switch if said enabling signal is in a first state.

4. The wake up circuit of claim 1, wherein said output decision circuit is further configured to receive at least one additional input signal in addition to said comparison output signal and said selector signal, said at least one additional input signal being a battery voltage signal, said output decision circuit responsive to said battery voltage signal to provide said selector output signal to said switch if said battery voltage signal is representative of a voltage level of said battery greater than a threshold voltage level.

5. The wake up circuit of claim 1, wherein said output decision circuit is further configured to receive at least one additional input signal in addition to said comparison output signal and said selector signal, said at least one additional input signal being a maximum wake up charge time signal, said output decision circuit responsive to said maximum wake up charge time signal to provide said selector output signal to said switch if said maximum wake up charge signal is representative of a continuous time of said output decision circuit providing said comparison output signal exceeding a maximum time interval.

6. The wake up circuit of claim 1, wherein said comparison circuit comprises an enor amplifier, said error amplifier is further configured to receive said first signal and said second signal and providing said comparison output signal.

7. A method comprising:

generating a first signal representative of a charging current level provided to a battery via a path and a second programmable signal representative of a predetermined wake up current level;

comparing said first signal to said second signal;

generating an analog comparison output signal in response to said first and second signals;

generating a selector signal having a first state and a second state; and

controlling the conduction state of a battery charging switch using said analog comparison output signal or said selector signal to control a charging current level provided to a battery;

wherein if said analog comparison output signal is used to control said battery charging switch, said switch is responsive to said analog comparison output signal to enter an intermediate conduction state to provide a current level to said battery representative of said predetermined wake up current level; and

wherein if said selector signal is used to control said battery charging switch, said switch is responsive to said first state to enter a full conduction state and responsive to said second state to turn off said switch.

8. The method of claim 7, wherein said first signal comprises a voltage signal, said switch comprising a field effect transistor having a gate terminal receiving said voltage signal.