Pulse generator
View Patent ↗Without shortening clock pulse duration serving as a unit time of a pulse generator, a pulse-width control is possible in which pulse duration varies in increments of a time length shorter than the unit time. A time width Ton_s of a pulse width finely dividing signal Vs from a DSP 17 varies by clock pulse duration T clk in response to variations in an output voltage Vo. A time control circuit 18 that has received the pulse width finely dividing signal Vs generates, in a control signal Vd, varying segments 30, 31 for making the time width of the pulse drive signal Vg vary by a shorter time ΔTd than the clock pulse duration T clk . Consequently, resolution of the time width of the pulse drive signal Vg is improved so as to be higher than the clock pulse duration T clk , which is time resolution of the DSP 17 itself.
1. A pulse generator for generating a control pulse that varies in pulse width comprising:
a variable signal output means for outputting pulse width dividing signals whose pulse time widths vary in increments of a unit time,
a time control means for detecting variations in time widths of said pulse width dividing signals to vary a pulse width of said control pulse in increments of a time length shorter than the unit time, wherein
the pulse width dividing signals output from said variable signal output means comprise:
a pulse width roughly dividing signal with a time width approximately equal to a pulse width of said control pulse and
a pulse width finely dividing signal for regulating the pulse width of said control pulse by said unit time,
wherein said time control means roughly determines the pulse width of said control pulse by means of said pulse width roughly dividing signal and then finely regulates the pulse width of said control pulse in increments of a time length shorter than said unit time by means of said pulse width finely dividing signal.
2. The pulse generator according to claim 1 , wherein said variable signal output means outputs said pulse width finely dividing signal ahead of said pulse width roughly dividing signal, while said time control means regulates a pulse width of said control pulse in increments of a time length shorter than said unit time after said pulse width roughly dividing signal has been output.
3. The pulse generator according to claim 2 , further comprising a pulse generating means for generating said control pulse when an input voltage exceeds a predetermined threshold value,
wherein when said pulse width roughly dividing signal begins to be output, said time control means generates a pulse generating signal for raising, at a predetermined gradient, a voltage level depending on said pulse width finely dividing signal with said pulse generating signal superposed on the voltage level and then said time control means regulates a pulse width of said control pulse in increments of a time length shorter than said unit time by turning the pulse generating signal into said input voltage.
4. The pulse generator according to claim 3 , wherein said time control means is provided with a bias voltage generating means for generating a voltage level depending on said pulse width finely dividing signal when said pulse width roughly dividing signal begins to be output.
5. The pulse generator according to claim 2 , further comprising a pulse generating means for generating said control pulse when an input voltage exceeds a predetermined threshold value,
wherein when said pulse width roughly dividing signal begins to be output, said time control means generates a pulse generating signal for lowering a voltage level from a peak value that exceeded the threshold value, at a predetermined gradient, depending on said pulse width finely dividing signal with said pulse generating signal superposed on the voltage level and then said time control means regulates a pulse width of said control pulse in increments of a time length shorter than said unit time by turning the pulse generating signal into said input voltage.
6. The pulse generator according to claim 5 , wherein said time control means is provided with a bias voltage generating means for generating a voltage level depending on said pulse width finely dividing signal when said pulse width roughly dividing signal begins to be output.
7. A pulse generator for generating a control pulse that varies in pulse width comprising:
a variable signal output means for outputting a pulse width roughly dividing signal with a time width approximately equal to a pulse width of said control pulse and a pulse width finely dividing signal whose phase difference from a phase of said pulse width roughly dividing signal varies by a unit time, and
a time control means for roughly determining the pulse width of said control pulse and detecting variations in said phase difference to vary a pulse width of said control pulse in increments of a time length shorter than said unit time.