Switching voltage regulator with low current trickle mode
First Claim
1. A voltage regulator for regulating a voltage applied to a load drawing a load current, the regulator comprising:
- a switching regulator portion, the switching regulator portion comprising;
a first controller that receives a feedback signal related to an output voltage of the regulator and switches a first transistor at a duty cycle necessary to maintain an output voltage of the regulator at a regulated voltage when load currents exceed a first threshold current, the first controller intermittently applying a first drive signal to the first transistor for turning on the first transistor during times when load currents exceed the first threshold current, and a non-switching regulator portion comprising;
a second controller that detects when a load current is below the first threshold current and, in response, stops switching the first transistor and applies a constant second drive signal to the first transistor, different from the first drive signal, to cause the first transistor to conduct a trickle current that is below the first threshold current.
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Accused Products
Abstract
For load currents greater than a threshold current, the voltage regulator operates in a conventional manner by fully turning on and off one or more switching transistors at a duty cycle necessary to maintain the output voltage a regulated voltage. Upon a load current below a threshold being detected, a controller stops the switching of the transistor(s) and applies a reduced drive signal to the high side transistor so as to apply a constant trickle current to the load. Unnecessary components are shut down to save power. When the output voltage falls below a threshold, the normal switching routine is resumed to recharge the regulator'"'"'s output capacitor to a certain level, and the regulator once again enters the light load current mode. By not completely shutting down the transistors at light load currents, as in done in a conventional intermittent-operation mode, there is lower power loss by less frequent switching of the transistor(s).
37 Citations
26 Claims
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1. A voltage regulator for regulating a voltage applied to a load drawing a load current, the regulator comprising:
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a switching regulator portion, the switching regulator portion comprising;
a first controller that receives a feedback signal related to an output voltage of the regulator and switches a first transistor at a duty cycle necessary to maintain an output voltage of the regulator at a regulated voltage when load currents exceed a first threshold current, the first controller intermittently applying a first drive signal to the first transistor for turning on the first transistor during times when load currents exceed the first threshold current, and a non-switching regulator portion comprising;
a second controller that detects when a load current is below the first threshold current and, in response, stops switching the first transistor and applies a constant second drive signal to the first transistor, different from the first drive signal, to cause the first transistor to conduct a trickle current that is below the first threshold current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method performed by a voltage regulator for regulating a voltage applied to a load drawing a load current, the method comprising:
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receiving a feedback signal related to an output voltage of the regulator;
switching a first transistor at a duty cycle necessary to maintain an output voltage of the regulator at a regulated voltage when load currents exceed a first threshold current, switching the first transistor comprising intermittently applying a first drive signal to the first transistor for turning on the first transistor during times when load currents exceed the first threshold current;
detecting when a load current is below the first threshold current; and
in response to detecting when a load current is below the first threshold current, stopping switching the first transistor and applying a constant second drive signal to the first transistor, different from the first drive signal, to cause the first transistor to conduct a trickle current that is below the first threshold current. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification