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US 7,598,718 B2Granted
Controller for DC to DC converter
AssigneeO2Micro International Limited
InventorsLaszlo Lipcsei, Serban-Mihai Popescu
Life of this patent
Estimating the term…
Abstract
A DC to DC converter to convert an input voltage to an output voltage. The DC to DC converter may include a pair of switches including a high side switch and a low side switch, an inductor coupled to the pair of switches; and a controller. The controller may be configured to estimate a zero crossing of an inductor current through the inductor without directly measuring said inductor current. An associated method is also provided.
Claims10
A DC to DC converter to convert an input voltage to an output voltage,
- said DC to DC converter comprising:
- a pair of switches comprising a high side switch and a low side switch;
- an inductor coupled to said pair of switches;
- and a controller configured to estimate a zero crossing of an inductor current through said inductor, said controller is further configured to provide a pulse width modulated (PWM) signal and a low side switch enabling signal, said low side switch responsive to said PWM signal and said low side switch enabling signal, said controller is further configured to provide a pulse width modulated (PWM) signal and a low side switch enabling signal, said controller comprising a capacitor, wherein said zero crossing of said inductor current is estimated by monitoring when a charge on said capacitor is less than a low voltage threshold, said controller including a first current source configured to provide a first current level and a second current source configured to provide a second current level, said controller further including a capacitor configured to be charged by a charging current equal to said second current level less said first current level during a first time interval, wherein said first time interval has a start time and an end time, said start time occurring when a charge level on said capacitor is substantially zero and said end time occurring when a charge level of said capacitor is greater than a charge threshold level, wherein said zero crossing of said inductor current is estimated by said start time of said first time interval.
1 more element
An apparatus comprising:
- a controller for a DC to DC converter, said controller configured to estimate a zero crossing of an inductor current through an inductor of said DC to DC converter, said controller is further configured to provide a pulse width modulated (PWM) signal and a low side switch enabling signal, said DC to DC converter having a high side switch and a low side switch, wherein said low side switch is responsive to said PWM signal and said low side switch enabling signal, said controller is further configured to provide a pulse width modulated (PWM) signal and a low side switch enabling signal, said controller comprising a capacitor, wherein said zero crossing of said inductor current is estimated by monitoring when a charge on said capacitor is less than a low voltage threshold, said controller configured to provide said PWM signal in a digital one state during a first time interval that is inversely proportional with an input voltage of said DC to DC converter less an output voltage of said DC to DC converter.
A method comprising:
- estimating a zero crossing of an inductor current through an inductor of a DC to DC convener by monitoring a charge on a capacitor of a controller for said DC to DC convener, said zero crossing occurring when a charge level of said capacitor is less than a low voltage threshold;
- providing a pulse width modulated (PWM) signal in a digital one state, a high side switch of said DC to DC converter switching ON in response to said PWM signal in said digital one state;
- and determining a time interval to maintain said PWM signal in said digital one state, said time interval inversely proportional with an input voltage of said DC to DC convener less an output voltage of said DC to DC convener said controller including a first current source configured to provide a first current level and a second current source configured to provide a second current level, said capacitor configured to be charged by a charging current equal to said second current level less said first current level during a first time interval, wherein said first time interval has a start time and an end time, said start time occurring when a charge level on said capacitor is substantially zero and said end time occurring when a charge level of said capacitor is greater than a charge threshold level, wherein said zero crossing of said inductor current is estimated by said start time of said first time interval.
Dependencies are inferred from the claim text.