Switching device of digital amplifier and method for driving the same
A switching device of a digital amplifier and a method for controlling the same are disclosed. In accordance with the present invention, a linearity is maintain even for a short pulse width since a data signal having a pulse width shorter than a predetermined length. Moreover, when an MLP signal is located at both sides of a compensating signal without overlapping with each other, a problem due to a common mode may be prevented.
1. A switching device for driving a load according to a data signal included in a frame of a PWM signal, comprising:
a controller for outputting an MLP signal; and a first compensating signal when [data]≦[MPC] is satisfied, wherein a pulse width of the first compensating signal is sum of [data] and [MLP], a second compensating signal; and a third compensation signal when [MPC]<[data]≦([MPC]+[MLP]) is satisfied, wherein a pulse width of the second compensation signal is a sum of [MPC] and [MLP], and a pulse width of the third compensation is [MLP]−([data]−[MPC]); and
a switch module for performing a switching operation according to the MLP signal, the first compensating signal, the second compensating signal and the third compensating signal (where [MPC] is a reference pulse width, [data] and [MLP] are pulse widths of the data signal and the MLP signal, respectively).
2. The device in accordance with claim 1 , wherein [MPC] satisfies [MLP]+[MPC]≦(a length of the frame−[MPW]) (where [MPW] is a minimum pulse width).
3. The device in accordance with claim 1 , wherein the MLP signal, each of the first compensating signal, the second compensating signal and the third compensating signal is located within the frame, and overlaps with each other with respect to a time axis.
4. The device in accordance with claim 1 , wherein each of the first compensating signal, the second compensating signal and the third compensating signal is located within the frame, and not overlapping with each other with respect to a time axis.
5. The device in accordance with claim 4 , wherein intervals between the MLP signal and the first compensating signal, and the second compensating signal and the third compensation signal are zero, respectively.
6. The device in accordance with claim 4 , wherein intervals between the MLP signal and the first compensating signal, and the second compensating signal and the third compensation signal are non-zero, respectively.
7. The device in accordance with claim 4 , wherein the MLP signal is located before and after the first compensating signal with each other with respect to the time axis.
8. A method for driving a switching device driving a load according to a data signal included in a frame of a PWM signal, the method comprising steps of:
(a) determining whether [data]≦[MPC] is satisfied;
(b) outputting an MLP signal; and a first compensating signal when [data]≦[MPC] is satisfied, wherein a pulse width of the first compensating signal is sum of [data] and [MLP];
(c) performing a switching operation according to the MLP signal and the compensating signal outputted in the step (b);
(d) determining whether [MPC]<[data]≦[MPC]+[MLP] is satisfied;
(e) outputting a second compensating signal; and a third compensating signal when [MPC]<[data]≦[MPC]+[MLP] is satisfied, wherein a pulse width of the second compensating signal is sum of [MPC] and [MLP], and a pulse width of the third compensating signal is [MLP]−([data]−[MPC]); and
(f) performing the switching operation according to the second compensating signal and the third compensating signal outputted in the step (e) (where [MPC] is a reference pulse width, [data] and [MLP] are pulse widths of the data signal and the MLP signal, respectively).
9. The method in accordance with claim 8 , wherein [MPC] satisfies ([MLP]+[MPC])≦(a length of the frame−[MPW]) (where [MPW] is minimum pulse width).
10. The method in accordance with claim 8 , wherein each of the MLP signal, the first compensating signal, the second compensating signal and the third compensating signal is located within the frame, and overlaps with each other with respect to a time axis.
11. The method in accordance with claim 8 , wherein each of the first compensating signal, the second compensating signal and the third compensating signal is located within the frame, and not overlapping with each other with respect to a time axis.
12. The method in accordance with claim 11 , wherein intervals between the MLP signal and the first compensating signal and the second compensating signal and the third compensation signal are zero, respectively.
13. The method in accordance with claim 11 , wherein intervals between the MLP signal and the first compensating signal and the second compensating signal and the third compensation signal are non-zero, respectively.
14. The method in accordance with claim 11 , wherein the MLP signal is located before and after the first compensating signal with each other with respect to the time axis.