Sensorless current sense for regulating inductor current in a buck converter
AssigneeFairchild Semiconductor Corporation
InventorJames Garrett
Life of this patent
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Abstract
A device and method for sensing an inductor current in an inductor is provided that generates a voltage signal proportionate to the inductor current if the inductor is connected to a positive supply and simulates the inductor current if the inductor is not connected to the positive supply. The voltage signal may be generated by sampling an input voltage from the inductor onto a capacitor if the inductor is connected to the positive supply. The inductor current may be simulated by generating a simulation current and pushing the simulation current onto the capacitor.
Claims16
A method for simulating an inductor current, comprising:
- utilizing a pulse width modulation signal to control a switch in voltage converter circuitry to cause an inductor in the voltage converter circuitry to be coupled to a positive supply when the switch is closed and decoupled from the positive supply when the switch is open;
- controlling track and hold circuitry in control circuitry to provide an inductor input voltage to an operational amplifier in the control circuitry when the pulse width modulation signal causes the switch to close;
- controlling the track and hold circuitry to stop providing the inductor input voltage to the operational amplifier when the pulse width modulation signal causes the switch to open;
- and
- simulating an inductor current when the switch is open by generating a voltage proportionate to the inductor current using at least a current source and a capacitor in the control circuitry, wherein the current source is controlled based at least on a resistance of the switch and an output voltage of the converter circuitry.
A device for simulating an inductor current, comprising:
- voltage converter circuitry including at least a switch to cause an inductor in the voltage converter circuitry to be coupled to a positive supply when the switch is closed and decoupled from the positive supply when the switch is open based on a pulse width modulation signal;
- and
- control circuitry including:
- track and hold circuitry to provide an inductor input voltage to an operational amplifier in the control circuitry when the pulse width modulation signal causes the switch to close, and stop providing the inductor input voltage to the operational amplifier when the pulse width modulation signal causes the switch to open;
- and
- a current source and a capacitor to simulate an inductor current when the switch is open by generating a voltage proportionate to the inductor current, wherein the current source is controlled based at least on a resistance of the switch and an output voltage of the converter circuitry.
Control circuitry for simulating an inductor current, comprising:
- an operational amplifier;
- track and hold circuitry to provide an inductor input voltage from an inductor in voltage converter circuitry to the operational amplifier when a pulse width modulation signal causes a switch in the voltage converter circuitry to close, and stop providing the inductor input voltage to the operational amplifier when the pulse width modulation signal causes the switch to open;
- and
- a current source and a capacitor to simulate an inductor current when the switch is open by generating a voltage proportionate to the inductor current, wherein the current source is controlled based at least on a resistance of the switch and an output voltage of the converter circuitry.
Dependencies are inferred from the claim text.