Method and system for communicating filter compensation coefficients for a digital power control system
View Patent ↗A method and system is provided for programming the digital filter compensation coefficients of a digitally controlled switched mode power supply within a distributed power system. The distributed power system comprises a plurality of point-of-load (POL) regulators each comprising at least one power switch adapted to convey power to a load and a digital controller adapted to control operation of the power switch responsive to a feedback measurement. The digital controller further comprises a digital filter having a transfer function defined by plural filter coefficients. A serial data bus operatively connects each of the plurality of POL regulators. A system controller is connected to the serial data bus and is adapted to communicate digital data to the plurality of POL regulators via the serial data bus. The digital data includes programming data for programming the plural filter coefficients. The system controller further comprises a user interface adapted to receive the programming data therefrom.
1. A power control system comprising:
a plurality of point-of-load (POL) regulators each comprising at least one power switch adapted to convey power to a load and a digital controller adapted to control operation of said at least one power switch responsive to a feedback measurement, said digital controller further comprising a digital filter having a transfer function defined by plural filter coefficients;
a serial data bus operatively connecting said plurality of POL regulators; and
a system controller connected to said serial data bus and adapted to communicate digital data to said plurality of POL regulators via said serial data bus, said digital data including programming data for programming said plural filter coefficients.
2. The power control system of claim 1 , wherein said system controller further comprises a user interface adapted to receive said programming data therefrom.
3. The power control system of claim 1 , wherein said digital filter further comprises an infinite impulse response filter.
4. The power control system of claim 3 , wherein said infinite impulse response filter provides the following transfer function G(z):
G
(
z
)
=
PWM
(
z
)
VEd
(
z
)
=
C
0
+
C
1
·
z
-
1
+
C
2
·
z
-
2
+
…
+
C
n
·
z
-
n
1
-
B
1
·
z
-
1
-
B
2
·
z
-
2
-
…
-
B
n
·
z
-
n
wherein PWM(z) is a digital control output, VEd(z) is an error signal, and said plural filter coefficients include C 0 . . . C n as input side filter coefficients and B 1 . . . B n as output side filter coefficients.
5. A power control system comprising:
a plurality of point-of-load (POL) regulators each comprising at least one power switch adapted to convey power to a load and a digital controller adapted to control operation of said at least one power switch responsive to a feedback measurement, said digital controller further comprising a digital filter having a transfer function defined by plural filter coefficients;
a serial data bus operatively connecting said plurality of POL regulators; and
a system controller connected to said serial data bus and adapted to communicate digital data to said plurality of POL regulators via said serial data bus, said digital data including programming data for programming said plural filter coefficients;
wherein said digital controller further comprises:
an analog-to-digital converter providing a digital error signal representing a difference between said feedback measurement and a reference value, said digital filter providing a digital control output based on a sum of current and previous error signals and previous control outputs;
an error controller adapted to modify operation of said digital filter upon an error condition; and
a digital pulse width modulator providing a control signal to said at least one power switch, said control signal having a pulse width corresponding to said digital control output.
6. A method of controlling a plurality of point-of-load (POL) regulators each comprising at least one power switch adapted to convey power to a load and a digital controller adapted to control operation of said at least one power switch responsive to a feedback measurement, said digital controller further comprising a digital filter having a transfer function defined by plural filter coefficients, the method comprising:
receiving programming data for programming said plural filter coefficients;
transmitting said programming data serially over a common data bus operably connected to said plurality of POL regulators; and
programming said plural filter coefficients of respective ones of said POL regulators in accordance with said programming data.
7. The method of claim 6 , wherein said receiving step further comprises receiving said programming data from a user.
8. The method of claim 6 , wherein said programming step further comprises programming said digital filter to provide the following transfer function G(z):
G
(
z
)
=
PWM
(
z
)
VEd
(
z
)
=
C
0
+
C
1
·
z
-
1
+
C
2
·
z
-
2
+
…
+
C
n
·
z
-
n
1
-
B
1
·
z
-
1
-
B
2
·
z
-
2
-
…
-
B
n
·
z
-
n
wherein PWM(z) is a digital control output, VEd(z) is an error signal, and said plural filter coefficients include C 0 . . . C n as input side filter coefficients and B 1 . . . B n as output side filter coefficients.
9. A method for programming a power control system including a plurality of point-of-load (POL) regulators each comprising at least one power switch adapted to convey power to a load and a digital controller adapted to control operation of said at least one power switch responsive to a feedback measurement, said digital controller further comprising a digital filter having a transfer function defined by plural filter coefficients, the method comprising:
displaying at least one screen simulating operation of an exemplary point-of-load regulator, said at least one screen including user selectable values for characteristics of at least one of said plurality of point-of-load regulators;
receiving user input to select said user selectable values;
calculating digital filter coefficients corresponding to said user input; and
selectively communicating data corresponding to said calculated filter coefficients to said at least one of said plurality of point-of-load regulators for programming said digital filter.
10. The method of claim 9 , wherein said user selectable values include at least one of component values, output voltage, output current, and load.
11. The method of claim 9 , further comprising programming said digital filter of said at least one of said plurality of point-of-load regulators using said data corresponding to said calculated filter coefficients.
12. The method of claim 9 , wherein said step of selectively communicating further comprises receiving said user input to selectively communicate said data to a selected one of said plurality of point-of-load regulators, plural ones of said plurality of point-of-load regulators assigned to a group, and all of said plurality of point-of-load regulators of said power control system.