Average input current estimation based on primary side current sense
AssigneeDialog Semiconductor GmbH
InventorsGuang Feng, Xiaoyan Wang, Liang Yan, Chuanyang Wang, Clarita Poon
Life of this patent
Estimating the term…
Abstract
The embodiments herein describe a power converter including a controller that estimates input current of the power converter. The controller estimates the input current without explicitly sensing the input current. The estimated input current can be used in various applications such as regulating power factor and total harmonic distortion as well as estimating current required to maintain proper operation of a dimmer switch in light emitting diode lamp systems.
Claims13
A switching power converter comprising:
- a magnetic component coupled to an input voltage and an output of the switching power converter;
- a switch coupled to the magnetic component to control current through at least part of the magnetic component, current through at least the part of the magnetic component generated while the switch is turned on and not being generated while the switch is turned off;
- a controller including a pin for sensing the current through at least the part of the magnetic component, the controller configured to generate a control signal to turn on or turn off the switch during a plurality of switching cycles of the switch;
- a resistive voltage divider including a first resistor and a second resistor, the current through at least the part of the magnetic component flows through the first resistor but not through the second resistor;
- and
- wherein the controller is configured to estimate an average input current of the switching power converter based on the following equation:
- I
- in_avg
- =
- 1
- 2
- ·
- D
- ISENSE
- R
- SNS
- ·
- T
- on
- T
- P
- where Iin—avg is the estimated average input current, DISENSE is a value representing a target peak current through at least the part of the magnetic component, RSNS is an impedance of the first resistor, Ton is an on-time of the switch during a switching cycle of the power converter, and Tp is a period of the switching cycle.
In a controller, a method of controlling a switching power converter, the switching power converter including a magnetic component coupled to an input voltage and an output of the switching power converter and a switch coupled to the magnetic component to control current through at least a part of the magnetic component, current through at least the part of the magnetic component being generated while the switch is turned on and not being generated while the switch is turned off, the switching power converter further including a resistive voltage divider including a first resistor and a second resistor, the current through at least the part of the magnetic component flows through the first resistor but not through the second resistor, the method comprising:
- generating a control signal to turn on or turn off the switch during a plurality of switching cycles of the switch;
- and
- estimating an average input current of the switching power converter based on the following equation:
- I
- in_avg
- =
- 1
- 2
- ·
- D
- ISENSE
- R
- SNS
- ·
- T
- on
- T
- P
- where Iin —avg is the estimated average input current, DISENSE is a value representing a target peak current through at least the part of the magnetic component, RSNS is an impedance of the first resistor, Ton is an on-time of the switch during a switching cycle of the power converter, and Tp, is a period of the switching cycle.
A switching power converter comprising:
- a magnetic component coupled to an input voltage and an output of the switching power converter;
- a switch coupled to the magnetic component to control current through at least part of the magnetic component, current through at least the part of the magnetic component generated while the switch is turned on and not being generated while the switch is turned off;
- a controller including a pin for sensing the current through at least the part of the magnetic component, the controller configured to generate a control signal to turn on or turn off the switch during a plurality of switching cycles of the switch;
- a resistive voltage divider including a first resistor and a second resistor, the current through at least the part of the magnetic component flows through the first resistor but not through the second resistor;
- wherein the controller is configured to supply a current via a path including the second resistor followed by the first resistor during a measurement mode of the controller to determine an impedance of the first resistor based on a voltage measured across the resistive voltage divider, the supplied current, and a relationship between the impedance of the first resistor and an impedance of the second resistor;
- and
- wherein the controller is configured to estimate an average input current of the switching power converter based on a value representing a target peak current through at least the part of the magnetic component and the determined impedance of the first resistor.
In a controller, a method of controlling a switching power converter, the switching power converter including a magnetic component coupled to an input voltage and an output of the switching power converter and a switch coupled to the magnetic component to control current through at least a part of the magnetic component, current through at least the part of the magnetic component being generated while the switch is turned on and not being generated while the switch is turned off, the switching power converter further including a resistive voltage divider including a first resistor and a second resistor, the current through at least the part of the magnetic component flows through the first resistor but not through the second resistor, the method comprising:
- generating a control signal to turn on or turn off the switch during a plurality of switching cycles of the switch;
- supplying a current via a path including the second resistor followed by the first resistor during a measurement mode of the controller;
- determining an impedance of the first resistor based on a voltage measured across the resistive voltage divider, the supplied current, and a relationship between the impedance of the first resistor and an impedance of the second resistor;
- and
- estimating an average input current of the switching power converter based on a value representing a target peak current through at least the part of the magnetic component and the determined impedance of the first resistor.
Dependencies are inferred from the claim text.