LED driver with dynamic power management
View Patent ↗A light emitting diode (LED) system implements a LED driver to drive a set of one or more LED strings. The LED driver includes a voltage source to provide an adjustable output voltage to a head end of each LED string of the set for a first duration and a second duration following the first duration. The LED driver further includes a feedback controller to control the voltage source to adjust the output voltage for the second duration based on a digital code value generated from a minimum tail voltage of one or more tail voltages of the set at a sample point of the first duration. The LED driver further includes a power controller to temporarily enable one or more components of the feedback controller for a sample period of the first duration, the sample period comprising the sample point.
1. A light emitting diode (LED) driver comprising:
a voltage source to provide an adjustable output voltage to a head end of each LED string of a set of one or more LED strings for a first duration and a second duration, the second duration following the first duration;
a feedback controller to control the voltage source to adjust the output voltage for the second duration based on a first digital code value generated from a first minimum tail voltage of one or more tail voltages of the set at a first sample point of the first duration; and
a power controller to temporarily enable a component of the feedback controller for a first sample period of the first duration comprising the first sample point and disable the component for the portion of the first duration that does not include the first sample period.
2. The LED driver of claim 1 , wherein:
the feedback controller further is to control the voltage source to adjust the output voltage for a third duration following the second duration based on a second digital code value generated from a second minimum tail voltage of one or more tail voltages of the set at a second sample point of the second duration; and
the power controller further is to temporarily enable the component for a second sample period comprising the second sample point and disable the component for the portion of the second duration that does not include the second sample period.
3. The LED driver of claim 1 , wherein:
the first duration comprises a first pulse width modulation (PWM) cycle; and
the second duration comprises a second PWM cycle.
4. The LED driver of claim 1 , wherein:
the first duration comprises a first display frame period;
the second duration comprises a second display frame period; and
the first sample point is a select point of a select pulse width modulation (PWM) cycle of the first display frame period.
5. The LED driver of claim 4 , wherein:
the select PWM cycle comprises a high-first PWM cycle; and
the select point comprises a point proximate to a start of the select PWM cycle.
6. The LED driver of claim 4 , wherein:
the select PWM cycle comprises a low-first PWM cycle; and
the select point comprises a point proximate to an end of the select PWM cycle.
7. The LED driver of claim 1 , wherein:
the feedback controller comprises:
an analog minimum select module to output the first minimum tail voltage of the one or more tail voltages of the set;
an analog-to-digital converter (ADC) to generate a second digital code value based on an output of the analog minimum select component;
a code processing module to generate the first digital code value based on the second digital code value;
a digital-to-analog converter (DAC) to generate a regulation voltage based on the first digital code value; and
an error amplifier to adjust a control signal based on a comparison of the regulation voltage to a feedback voltage representative of the output voltage, wherein the voltage source is to adjust the output voltage based on the control signal; and
wherein the one or more components temporarily enabled by the power controller comprises at least one of the analog minimum select module, the ADC, the code processing module, and the DAC.
8. A method comprising:
providing, for a first duration, a first voltage from a light emitting diode (LED) driver to a head end of each LED string of a set of one or more LED strings, each LED string having a corresponding tail voltage in response to the first voltage;
during the first duration, determining a first minimum tail voltage of one or more tail voltages of the set at a first sample point and generating a first digital code value based on the first minimum tail voltage using a feedback controller of the LED driver;
temporarily enabling a component of the feedback controller of the LED driver for a first sample period of the first duration and disabling the component for the portion of the first duration that does not include the first sample period, the first sample period comprising the first sample point; and
controlling the voltage source to adjust the output voltage for a second duration subsequent to the first duration based on the first digital code value.
9. The method of claim 8 , further comprising:
during the second duration, determining a second minimum tail voltage of one or more tail voltages of the set at a second sample point and generating a second digital code value based on the second minimum tail voltage using the feedback controller;
temporarily enabling the component of the feedback controller for a second sample period of the second duration and disabling the component for the portion of the second duration that does not include the second sample period, the second sample period comprising the second sample point; and
controlling the voltage source to adjust the output voltage for a third duration subsequent to the second duration based on the second digital code value.
10. The method of claim 9 , wherein:
the first duration comprises a first display frame period; and
the second duration comprises a second display frame period.
11. The method of claim 8 , wherein:
the first duration comprises a first display frame period;
the second duration comprises a second display frame period;
the first sample point is a select point of a select pulse width modulation (PWM) cycle of the first display frame period.
12. The method of claim 11 , wherein:
the select PWM cycle comprises a high-first PWM cycle; and
the select point comprises a point proximate to a start of the select PWM cycle.
13. The method of claim 11 , wherein:
the select PWM cycle comprises a low-first PWM cycle; and
the select point comprises a point proximate to an end of the select PWM cycle.
14. The method of claim 8 , wherein:
the feedback controller comprises:
an analog minimum select module to output the first minimum tail voltage of the one or more tail voltages of the set;
an analog-to-digital converter (ADC) to generate a second digital code value based on an output of the analog minimum select component;
a code processing module to generate the first digital code value based on the second digital code value;
a digital-to-analog converter (DAC) to generate a regulation voltage based on the first digital code value; and
an error amplifier to adjust a control signal based on a comparison of the regulation voltage to a feedback voltage representative of the output voltage, wherein the voltage source is to adjust the output voltage based on the control signal; and
wherein temporarily enabling one or more components of the feedback controller comprises temporarily enabling at least one of the analog minimum select module, the ADC, the code processing module, and the DAC.
15. A light emitting diode (LED) system comprising:
a LED panel comprising a set of one or more LED strings;
a voltage source to provide, for a first duration, a first voltage to a head end of each LED string of the set, each LED string of the set having a corresponding tail voltage in response to the first voltage;
a feedback controller coupled to the LED panel and the voltage source, the feedback controller to:
determine a minimum tail voltage of one or more tail voltages of the set at a sample point of a sample period of the first duration;
generate a digital code value based on the minimum tail voltage; and
control the voltage source to adjust the output voltage for a second duration subsequent to the first duration based on the digital code value; and
a power controller coupled to the feedback controller, the power controller to:
enable one or more components of the feedback controller for the sample period of the first duration; and
disable the one or more components of the feedback controller for the portion of the first duration that does not include the sample period.
16. The LED system of claim 15 , wherein:
the first duration comprises a first display frame period;
the second duration comprises a second display frame period;
the sample point is a select point of a select pulse width modulation (PWM) cycle of the first display frame period.
17. The LED system of claim 16 , wherein the feedback controller further is to align the select PWM cycle with one or more concurrent PWM cycles.
18. The LED system of claim 16 , wherein:
the select PWM cycle comprises a high-first PWM cycle; and
the select point comprises a point proximate to a start of the select PWM cycle.
19. The LED system of claim 16 , wherein:
the select PWM cycle comprises a low-first PWM cycle; and
the select point comprises a point proximate to an end of the select PWM cycle.
20. The LED system of claim 15 , wherein:
the feedback controller comprises:
an analog minimum select module to output the minimum tail voltage of the one or more tail voltages of the set;
an analog-to-digital converter (ADC) to generate a second digital code value based on an output of the analog minimum select component;
a code processing module to generate the first digital code value based on the second digital code value;
a digital-to-analog converter (DAC) to generate a regulation voltage based on the first digital code value; and
an error amplifier to adjust a control signal based on a comparison of the regulation voltage to a feedback voltage representative of the output voltage, wherein the voltage source is to adjust the output voltage based on the control signal; and
wherein the one or more components of the feedback controller comprises at least one of the analog minimum select module, the ADC, the code processing module, and the DAC.