Circuit arrangement and method for producing a pulse width modulated signal
AssigneeSiemens Aktiengesellschaft
InventorMartin Götzenberger
Life of this patent
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Abstract
A circuit arrangement for producing a PWM signal (x) having a prescribed PWM frequency from two signals (a, b) which are input into the circuit arrangement, where the PWM signal (x) has a duty ratio which varies with the difference between the signals (a, b) comprises a signal generator (16) for producing a cyclic comparison signal, particularly an essentially trapezoidal signal (d), whose frequency is the same as the PWM frequency and whose shape is dependent on one (a) of the two signals (a, b), and a comparator (18) for comparing the other (b) of the two signals (a, b) with the comparison signal (d) and for providing the PWM signal (x) at the output of the comparator.
Claims14
A circuit arrangement for producing a PWM signal having a prescribed PWM frequency from first and second signals input into the circuit arrangement, the PWM signal having a duty ratio varying essentially linearly with a difference between the first and second signals, said arrangement comprising:
- a signal generator for generating a cyclic essentially trapezoidal comparison signal having the same frequency as the prescribed PWM frequency, the shape of said trapezoidal signal dependent on one of the first or second signals, and
- a comparator for comparing the non-dependent signal of the first and second signals with the cyclic trapezoidal comparison signal and for providing the PWM signal at the output of the comparator.
A control loop comprising a circuit arrangement comprising:
- a prescribed PWM frequency for a PWM signal, said PWM frequency from first and second signals input into the circuit arrangement, the PWM signal having a duty ratio varying with a difference between the first and second signals, said variance being essentially linearly with the difference,
- a signal generator for generating a cyclic comparison signal, said cyclic comparison signal being essentially a trapezoidal signal having the same frequency as the PWM frequency, and the shape of said cyclic comparison signal dependent on one of the first and second signals, and
- a comparator for comparing the other non-dependent signal of the first and second signals with the comparison signal and for providing a PWM signal at the output of the comparator,
- wherein the PWM signal produced by the circuit arrangement is a manipulated variable from a control loop formed from the first and second signals used as the control loop's reference variable and controlled variable.
A method for producing a PWM signal having a prescribed PWM frequency from first and second signals, wherein the PWM signal has a duty ratio varying essentially linearly with a difference between the first and second signals, said method comprising:
- producing a cyclic comparison signal, said cyclic comparison signal being an essentially trapezoidal signal having the same frequency as the prescribed PWM frequency and whose shape is dependent on one of the first and second signals, and
- comparing the other non-dependent signal of the first and second signals with the comparison signal to provide the PWM signal as the result of the comparison.
A method for producing a manipulated variable from a control loop from the signals used as the control loop's reference variable and controlled variable, said method comprising:
- producing a PWM signal having a prescribed PWM frequency from first and second signals, the PWM signal having a duty ratio varying essentially linearly with a difference between the first and second signals,
- producing a cyclic essentially trapezoidal comparison signal having the same frequency as the prescribed PWM frequency and whose shape is dependent on one of the first and second signals, and
- comparing the other non-dependent signal of the first and second signals with the cyclic comparison signal in order to provide the PWM signal.
Dependencies are inferred from the claim text.