Primary side regulator
View Patent ↗A primary side regulator according to an embodiment includes a power switch connected to a primary winding, a secondary winding configured to be insulated and coupled to the primary winding, a diode connected between the secondary winding and an output terminal, and an auxiliary winding coupled to the primary winding, and insulated and coupled to the secondary winding. The primary side regulator controls a switching operation of the power switch using a voltage obtained by filtering at least one of an estimation voltage signal corresponding to an output voltage of the output terminal and an estimation current signal corresponding to an output current flowing through the diode.
1. A primary side regulator, comprising:
a power switch connected to a primary winding;
a secondary winding;
a diode connected between the secondary winding and an output terminal; and
an auxiliary winding coupled to the primary winding,
wherein the primary side regulator controls a switching operation of the power switch by comparing one of a voltage average error based on an estimation voltage signal corresponding to an output voltage of the output terminal and a current average error based on an estimation current signal corresponding to an output current flowing through the diode with a current flowing through the power switch, and
wherein the primary side regulator filters at least one of the estimation voltage signal and the estimation current signal.
2. The primary side regulator of claim 1 , further comprising:
a peak detector configured to detect a peak voltage of a first sensing voltage according to the current flowing through the power switch for each switching period of the power switch; and
a current calculator configured to generate the estimation current signal by multiplying the peak voltage, the switching period of the power switch and an on signal corresponding to a turn-on period of the diode.
3. The primary side regulator of claim 1 , further comprising:
a sample and hold unit configured to sample and hold a second sensing voltage according to an auxiliary voltage of the auxiliary winding at a time at which a current does not flow through the diode after the power switch is turned off, and generate the estimation voltage signal.
4. The primary side regulator of claim 1 , further comprising:
a first filter configured to perform a low pass filtering operation on the estimation current signal, and generate a current average.
5. The primary side regulator of claim 4 , further comprising:
a first error amplifier configured to amplify a difference between the current average and a predetermined first reference voltage, and generate the current average error.
6. The primary side regulator of claim 1 , further comprising:
a digital filter configured to convert the estimation current signal into a digital signal, calculate an average value of the digital signal, convert the calculated average value into an analog signal, and generate a current average.
7. The primary side regulator of claim 6 , further comprising:
a first error amplifier configured to amplify a difference between the current average and a predetermined first reference voltage, and generate the current average error.
8. The primary side regulator of claim 1 , further comprising:
a second filter configured to perform a low pass filtering operation on the estimation voltage signal, and generate a voltage average.
9. The primary side regulator of claim 8 , further comprising:
a second error amplifier configured to amplify a difference between the voltage average and a predetermined second reference voltage, and generate the voltage average error.
10. The primary side regulator of claim 1 , further comprising:
a digital filter configured to convert the estimation voltage signal into a digital signal, calculate an average value of the digital signal, convert the calculated average value into an analog signal, and generate a voltage average.
11. The primary side regulator of claim 10 , further comprising:
a second error amplifier configured to amplify a difference between the voltage average and a predetermined second reference voltage, and generate the voltage average error.
12. The primary side regulator of claim 1 , wherein the primary side regulator is configured to:
generate a current average by performing a low pass filtering operation on the estimation current signal;
generate the current average error by amplifying a difference between the current average and a predetermined first reference voltage;
generate a voltage average by performing a low pass filtering operation on the estimation voltage signal;
generate the voltage average error by amplifying a difference between the voltage average and a predetermined second reference voltage; and
turn the power switch off when a current flowing through the power switch reaches at least one of the current average error and the voltage average error.
13. The primary side regulator of claim 1 , wherein the primary side regulator is configured to:
generate a current average by performing a low pass filtering operation on the estimation current signal;
generate the current average error by amplifying a difference between the current average and a predetermined first reference voltage;
generate the voltage average error by amplifying a difference between the estimation voltage signal and a predetermined second reference voltage; and
turn the power switch off when a current flowing through the power switch reaches at least one of the current average error and the voltage average error.
14. The primary side regulator of claim 1 , wherein the primary side regulator is configured to:
generate the current average error by amplifying a difference between the estimation current signal and a predetermined first reference voltage;
generate a voltage average by performing a low pass filtering operation on the estimation voltage signal;
generate the voltage average error by amplifying a difference between the voltage average and a predetermined second reference voltage; and
turn the power switch off when a current flowing through the power switch reaches at least one of the current average error and the voltage average error.
15. The primary side regulator of claim 1 , wherein the primary side regulator is configured to:
calculate a digital current average value by converting the estimation current signal into a digital signal;
generate a current average by converting the calculated digital current average value into an analog signal;
generate the current average error by amplifying a difference between the current average and a predetermined first reference voltage;
calculate a digital voltage average value by converting the estimation voltage signal into a digital signal;
generate a voltage average by converting the calculated digital voltage average value into an analog signal;
generate the voltage average error by amplifying a difference between the voltage average and a predetermined second reference voltage; and
turns the power switch off when a current flowing through the power switch reaches at least one of the current average error and the voltage average error.
16. The primary side regulator of claim 1 , wherein the primary side regulator is configured to:
calculate a digital current average value by converting the estimation current signal into a digital signal;
generate a current average by converting the calculated digital current average value into an analog signal;
generate the current average error by amplifying a difference between the current average and a predetermined first reference voltage;
generate the voltage average error by amplifying a difference between the estimation voltage signal and a predetermined second reference voltage; and
turn the power switch off when a current flowing through the power switch reaches at least one of the current average error and the voltage average error.
17. The primary side regulator of claim 1 , wherein the primary side regulator is configured to:
generate the current average error by amplifying a difference between the estimation current signal and a predetermined first reference voltage;
calculate a digital voltage average value by converting the estimation voltage signal into a digital signal;
generate a voltage average by converting the calculated digital voltage average value into an analog signal;
generate the voltage average error by amplifying a difference between the voltage average and a predetermined second reference voltage; and
turn the power switch off when a current flowing through the power switch reaches at least one of the current average error and the voltage average error.
18. A primary side regulator, comprising:
a power switch connected to a primary winding;
a secondary winding;
a diode connected between the secondary winding and an output terminal; and
an auxiliary winding coupled to the primary winding,
wherein the primary side regulator controls a switching operation of the power switch using a current average obtained by filtering an estimation current signal corresponding to an output current flowing through the diode.
19. The primary side regulator of claim 18 , further comprising:
a peak detector configured to detect a peak voltage of a first sensing voltage according to a current flowing through the power switch for each switching period of the power switch; and
a current calculator configured to generate the estimation current signal by using the peak voltage, the switching period of the power switch and an on signal corresponding to a turn-on period of the diode.
20. A primary side regulator, comprising:
a power switch connected to a primary winding;
a secondary winding;
a diode connected between the secondary winding and an output terminal;
an auxiliary winding coupled to the primary winding; and
a sample and hold unit configured to sample and hold a second sensing voltage according to an auxiliary voltage of the auxiliary winding at a time at which a current does not flow through the diode after the power switch is turned off,
wherein the primary side regulator controls a switching operation of the power switch using a voltage average obtained by filtering an output of the sample and hold unit.