DC/DC converter with dynamic offset compensation
View Patent ↗The present invention provides a DC/DC up-converter ( 100 ) that is implemented in form of a switching regulator ( 100 ). The DC/DC converter ( 100 ) makes use of a switching transistor ( 104 ) that controls a charging current for a capacitive element ( 112 ). Moreover, the DC/DC converter ( 100 ) provides control means ( 106, 140 ) to realize an accurate switch-off of the switching transistor ( 104 ) at a point of time when the charging current equals zero. Deviations of a first control means ( 106 ) are detected by means of a second control means ( 140 ) and a corresponding offset control signal ( 142 ) is generated for reducing the first control means' offset in a successive duty cycle.
1. A DC/DC converter having a switching transistor for controlling the flow of a current for charging of a capacitive element, the DC/DC converter comprising:
first control means adapted to initiate a switch-off of the switching transistor in response to a detection of a zero crossing of the current; and
second control means adapted to detect a voltage peak across the switching transistor, the voltage peak being indicative of the switching transistor's switch-off prior to the zero crossing of the current due to an offset of the first control means, and generate an offset control signal for reducing the offset of the first control means, the offset control signal being provided to the first control means.
2. The DC/DC converter according to claim 1 , wherein the second control means is implemented as a comparator being adapted to detect the voltage peak across the switching transistor.
3. The DC/DC converter according to claim 1 , wherein the second control means is adapted to generate an offset control signal for delaying the switching transistor's switch-off if the second control means detects the voltage peak being indicative of a switch-off of the switching transistor prior to a zero crossing of the current.
4. The DC/DC converter according to claim 1 , wherein the second control means is adapted to generate an offset control signal for advancing the switching transistor's switch-off if the second control means does not detect the voltage peak being indicative of a switch-off of the switching transistor prior to a zero crossing of the current.
5. The DC/DC converter according to claim 1 , wherein the size of the voltage peak detected by the second control means determines the magnitude of the offset control signal.
6. The DC/DC converter according to claim 1 , wherein the first control means is adapted to enable the second control means.
7. The DC/DC converter according to claim 1 , wherein the DC/DC converter provides DC/DC up-conversion.
8. The DC/DC converter according to claim 1 , wherein the second control means is adapted to detect a voltage peak having a duration in the range of nanoseconds.
9. A method of operating a DC/DC converter having a switching transistor adapted to control the flow of a current for charging a capacitive element the DC/DC converter further having first control means adapted to initiate a switch-off of the switching transistor in response to a detection of a zero crossing of the current, the method of operating comprising the steps of:
detecting a voltage peak across the switching transistor, the voltage peak being indicative of the switching transistor's switch-off prior to the zero crossing of the current due to an offset of the first control means; and
generating an offset control signal by a second control means and providing the offset control signal to the first control means in order to reduce the offset of the first control means.
10. The method according to claim 9 , wherein generating an offset control signal by the second control means further comprises generating an offset control signal for delaying the switching transistor's switch-off if the second control means detects the voltage peak being indicative of a switch-off of the switching transistor prior to a zero crossing of the current.
11. The method claim according to claim 9 , wherein generating an offset control signal by the second control means further comprises generating an offset control signal for advancing the switching transistor's switch-off if the second control means does not detect the voltage peak being indicative of a switch-off of the switching transistor prior to a zero crossing of the current.
12. The method according to claim 9 further comprising: providing DC/DC up-conversion.
13. A battery driven electronic device comprising:
a DC/DC converter comprising:
first control means adapted to initiate a switch-off of the switching transistor in response to a detection of a zero crossing of the current; and
second control means adapted to detect a voltage peak across the switching transistor, the voltage peak being indicative of the switching transistor's switch-off prior to the zero crossing of the current due to an offset of the first control means, and generate an offset control signal for reducing the offset of the first control means, the offset control signal being provided to the first control means.
14. The device according to claim 13 , wherein the second control means is implemented as a comparator adapted to detect the voltage peak across the switching transistor.
15. The device according to claim 14 , wherein the size of the voltage peak detected by the second control means determines the magnitude of the offset control signal.
16. The device according to claim 13 , wherein the second control means is adapted to generate an offset control signal for delaying the switching transistor's switch-off if the second control means detects the voltage peak being indicative of a switch-off of the switching transistor prior to a zero crossing of the current.
17. The device according to claim 13 , wherein the second control means is adapted to generate the offset control signal for advancing the switching transistor's switch-off if the second control means does not detect the voltage peak being indicative of a switch-off of the switching transistor prior to a zero crossing of the current.
18. The device according to claim 13 , wherein the first control means is adapted to enable the second control means.
19. The device according to claim 13 , wherein the device provides DC/DC up-conversion.
20. The device according to claim 13 , wherein the second control means is adapted to detect the voltage peak having a duration in the range of nanoseconds.