Switch mode power supply control systems
First Claim
1. A switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having:
- an input to receive an output voltage dependent feedback signal;
an output for driving said power switching device; and
a controller to provide a switching control signal to said output responsive to said feedback signal from said input, said switching control signal having a switching cycle including an ON portion for switching on said power switching device, and wherein said controller is configured to select one of a plurality of discrete pulse widths for said ON portion of said switching cycle using at least one stored pulse width, and to vary a duration of said switching cycle responsive to said feedback signal.
6 Assignments
0 Petitions
Accused Products
Abstract
We describe a switch mode power supply (SMPS) controller employing a combination of pulse frequency and pulse width modulation. The controller employs a “gear box” control scheme using two complementary control loops, one for real-time control of the SMPS using PFM and a second using a PWM control scheme which monitors the switching frequency and, at defined operating points, adjusts the pulse width up or down through a set of pre-determined values. This can be considered analogous to the gearbox of a motor vehicle with the SMPS pulse width, switching frequency and output power roughly corresponding to the vehicle'"'"'s gear ratio, engine speed and road speed respectively.
78 Citations
34 Claims
-
1. A switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having:
-
an input to receive an output voltage dependent feedback signal;
an output for driving said power switching device; and
a controller to provide a switching control signal to said output responsive to said feedback signal from said input, said switching control signal having a switching cycle including an ON portion for switching on said power switching device, and wherein said controller is configured to select one of a plurality of discrete pulse widths for said ON portion of said switching cycle using at least one stored pulse width, and to vary a duration of said switching cycle responsive to said feedback signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 34)
-
-
14. A method of operating a switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having:
-
an input to receive an output voltage dependent feedback signal;
an output for driving said power switching device; and
a controller to provide a switching control signal to said output responsive to said feedback signal from said input, said switching control signal having a switching cycle including an ON portion for switching on said power switching device, the method comprising;
selecting one of a plurality of discrete pulse widths for said ON portion of said switching cycle using at least one stored pulse width; and
varying a duration of said switching cycle responsive to said feedback signal to regulate an output of said switch mode power supply. - View Dependent Claims (15, 16, 25)
-
-
17. A switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having a plurality of operating power ranges each defining a range of average power transferred per switching cycle by said power switching device, each said range being defined by a combination of:
- one of a plurality of pre-determined pulse widths, and a range of durations of said switching cycle.
- View Dependent Claims (18)
-
19. A switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having:
-
an input to receive a power supply output dependent feedback signal;
an output for driving said power switching device; and
a digital controller to provide a switching control signal from said output responsive to said feedback signal from said input, said switching control signal having a switching cycle including an ON portion for switching on said power switching device, wherein said ON portion of said switching cycle is followed by a OFF portion for switching off said power device, wherein said controller is configured to end said OFF portion of said switching cycle and restart said ON portion of said switching cycle responsive to said feedback signal; and
wherein said feedback signal comprises a variable level signal, and wherein said controller is configured to compare said feedback signal level with a reference level to determine a timing of said switching cycle restart.
-
-
20. A switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having:
-
an input to receive an output voltage dependent feedback signal;
an output for driving said power switching device; and
a digital controller to provide a switching control signal from said output responsive to said feedback signal from said input; and
wherein said controller is configured to vary said pulse frequency and pulse width in combination to maintain said pulse frequency at greater than an audio frequency when said pulse width is greater than a minimum pulse width. - View Dependent Claims (21, 22)
-
-
23. A switch mode power supply controller employing a combination of pulse frequency modulation and pulse width modulation to control a power switching device, the controller having:
-
an input to receive a power supply output dependent feedback signal;
an output for driving said power switching device; and
a digital controller to provide a switching control signal from said output responsive to said feedback signal from said input; and
wherein said controller comprises;
a system counter coupled to said input;
an output pulse generator coupled to said an output of system counter and to said output;
a pulse width look-up table having an output coupled to a pulse width control input of said output pulse generator; and
a pulse width controller coupled to said system counter output and to said pulse width look-up table to select a pulse width for said pulse generator using said look-up table. - View Dependent Claims (24)
-
- 26. A pulse width and frequency modulation (PWFM) SMPS (switch mode power supply) controller configured to control a drive signal to a power switching device of said SMPS by PWFM in response to a feedback signal responsive to an output condition of said SMPS, wherein said controller has a variable gearing ratio, said gearing ratio determining a range of available pulse widths for said PWFM, associated with a frequency of said PWFM, determining an operating power range for said SMPS.
Specification