Controllers for DC/DC converters
A controller for a DC/DC converter includes multiple signal generators and a control circuit. The signal generators generate multiple pulse signals, each signal generator generating a corresponding pulse signal of the pulse signals and controlling the corresponding pulse signal to have a predetermined pulse width by counting a same preset number of cycles of a same oscillating signal. The control circuit selectively activates the signal generators according to an output of the DC/DC converter to generate the pulse signals.
1. A controller for a DC/DC converter, comprising:
a plurality of signal generators that generates a plurality of pulse signals having a predetermined pulse width by counting cycles of a same first oscillating signal; and
a control circuit, coupled to said signal generators, that selectively activates said signal generators according to an output of said DC/DC converter to generate said pulse signals,
wherein each signal generator of said signal generators, in response to a trigger signal from said control circuit, starts to count said cycles of said same first oscillating signal and generates a corresponding pulse signal of said pulse signals at a first level, and wherein said each signal generator controls said corresponding pulse signal to have a second level when a count value obtained by counting said cycles of said same first oscillating signal equals a preset end value.
2. The controller as claimed in claim 1 , wherein said predetermined pulse width is determined by multiplying said preset end value with a cycle period of said same first oscillating signal.
3. The controller as claimed in claim 1 , wherein said signal generators control said pulse signals to have substantially the same pulse width by counting a same preset number of cycles of said same first oscillating signal.
4. The controller as claimed in claim 1 , wherein said DC/DC converter comprises a plurality of switches and a plurality of inductors, and wherein each pulse signal of said pulse signals controls a pair of switches of said plurality of switches to control a current flowing through a corresponding inductor of said plurality of inductors.
5. The controller as claimed in claim 4 , wherein said current increases if said each pulse signal is in a first state, and wherein said current decreases if said each pulse signal is in a second state.
6. The controller as claimed in claim 4 , wherein said signal generators generate said pulse signals, by counting a same preset number of cycles of said same first oscillating signal, to control a plurality of currents flowing through said inductors to have substantially the same ripple amplitude.
7. The controller as claimed in claim 1 , further comprising a comparator operable for comparing said output of said DC/DC converter with a reference level.
8. The controller as claimed in claim 7 , wherein if said output is less than said reference level, then said control circuit increases said output by activating at least one signal generator of said signal generators one-by-one to generate at least one pulse signal, each of said at least one signal generator activated in response to a clock pulse of a second oscillating signal; and wherein if said output increases to said reference level, then said control circuit halts the activation of said signal generators.
9. The controller as claimed in claim 1 , wherein said control circuit comprises a shift register that is controlled by a second oscillating signal and that causes said control circuit to generate, in response to a plurality of cycles of said second oscillating signal, a plurality of trigger signals to selectively activate said signal generators.
10. A method for controlling a DC/DC converter, comprising:
selectively activating a plurality of signal generators according to an output of said DC/DC converter to generate a plurality of pulse signals; and
controlling each pulse signal of said pulse signals to have a predetermined pulse width, said controlling comprising:
controlling said each pulse signal to have a first level in response to a trigger signal;
starting to count cycles of a same oscillating signal in response to said trigger signal; and
controlling said each pulse signal to have a second level when a count value obtained by counting said cycles of said same oscillating signal equals a same preset end value.
11. The method as claimed in claim 10 , wherein said selectively activating comprises:
activating at least one signal generator of said signal generators one by one to generate at least one pulse signal if said output is less than a reference level, wherein each of said at least one signal generator is activated in response to a clock pulse of a clock signal; and
halting the activation of said signal generators if said output increases to said reference level.
12. A controller for a DC/DC converter, comprising:
a plurality of terminals that provide a plurality of pulse signals; and
control circuitry that is coupled to said terminals and selectively activates a plurality of signal generators according to an output of said DC/DC converter to generate said pulse signals, and controls each pulse signal of said pulse signals to have a predetermined pulse width by counting cycles of a same oscillating signal, wherein each signal generator of said signal generators, in response to a trigger signal, starts to count said cycles of said same first oscillating signal and generates a corresponding pulse signal of said pulse signals at a first level, and wherein said each signal generator controls said corresponding pulse signal to have a second level when a count value obtained by counting said cycles of said same first oscillating signal equals a preset end value.
13. The controller as claimed in claim 12 , wherein said predetermined pulse width is determined by multiplying said preset end value with a cycle period of said same oscillating signal.
14. The controller as claimed in claim 12 , wherein said signal generators control said pulse signals to have substantially the same pulse width by counting a same preset number of cycles of said same oscillating signal.
15. The controller as claimed in claim 12 , wherein said DC/DC converter comprises a plurality of switches and a plurality of inductors, and wherein said each pulse signal controls a pair of switches of said plurality of switches to control a current flowing through a corresponding inductor of said plurality of inductors.
16. The controller as claimed in claim 15 , wherein said current increases if said each pulse signal is in a first state, and wherein said current decreases if said each pulse signal is in a second state.
17. The controller as claimed in claim 15 , wherein said signal generators generate said pulse signals, by counting a same preset number of cycles of said same oscillating signal, to control a plurality of currents flowing through said inductors to have substantially the same ripple amplitude.
18. The controller as claimed in claim 12 , wherein if said output is less than a reference level, then said control circuitry increases said output by activating at least one signal generator of said signal generators one-by-one to generate at least one pulse signal, each of said at least one signal generator activated in response to a clock pulse of a clock signal; and wherein if said output increases to said reference level, then said control circuitry halts the activation of said signal generators.