Signal amplifying method, signal amplifier and devices related therewith

An analog signal amplifying method of an analog signal amplifier, the method comprising the steps of:

• outputting a first sawtooth-wave having a frequency much larger than a maximum frequency of input signal of the amplifier, an amplitude identical to or a little larger than a maximum amplitude of the input signal and a predetermined period;
• comparing the first sawtooth-wave with the input signal to output a first pulse of high level while the amplitude of the first sawtooth-wave is larger than that of the input signal;
• outputting a second pulse having a small width in the form of one-short type at every starting point of high level regions of the first pulse;
• outputting a second sawtooth-wave having an amplitude identical to or a little larger than a maximum amplitude of output signal of the amplifier and the same period and phase as that of the first sawtooth-wave;
• corresponding the respective starting points of high level regions of the second pulse to the second sawtooth-wave to continuously generate a first output voltage on the basis of the second sawtooth-wave voltage position where the starting points and the high level regions are corresponded with each other;
• outputting a third sawtooth-wave having reversed phase of the second sawtooth-wave;
• corresponding the respective starting points of high level regions of the second pulse to the third sawtooth-wave to continuously generate a second output voltage on the basis of the third sawtooth-wave voltage position where the starting points and the third sawtooth-wave are corresponded with each other;
• charging the generated the first and second voltages into a condenser by an analog switch, contantly keeping the voltage charged in it and eliminating valleys of the output waveforms to be easily filtered;
• and
• obtaining a double magnitude of output signal by utilizing the first and second outputs.

A sawtooth-wave generating circuit used for an analog signal amplifying circuit, the circuit comprising:

• a clock generator (7-A) for generating clocks;
• a second sawtooth-wave generator (7-B) for making pulses generated from the clock generator (7-A) into positive and negative pulse, obtaining a continuous second sawtooth-wave of output signal level by driving a condenser (C3) discharging circuit (Q1) of output voltage level with the positive pulse and resetting the sawtooth-wave at every positive pulse and finally generating an input signal level of the first sawtooth-wave by using the second sawtooth-wave;
• and
• a third sawtooth-wave generator (7-C) for reducing an output impedance of the second sawtooth-wave by a buffer circuit (Q3) and simultaneously driving an output voltage level of a condenser (C5) discharging circuit (Q4) with the negative pulse generated from the clock generator to reset the sawtooth-wave at every negative pulse and finally obtaining a continuous third sawtooth-wave, and wherein the third sawtooth-wave is outputted in the form of the lower output impedance reduced by a buffer circuit (Q6) to thereby generate two sawtooth-waves having same periods and different phases reversed oppositely with each other.

A sawtooth-wave generating circuit used for an analog signal amplifying circuit, the circuit comprising:

• a clock generator (7-A) for generating clocks;
• a second sawtooth-wave generator (7-B) for generating a second sawtooth-wave of output signal level by using clocks of the clock generator (7-A) and, simultaneously, generating a first sawtooth-wave of input signal level by using the second sawtooth-wave;
• a third sawtooth-wave generator (7-C) for generating a third sawtooth-wave of output signal level having a reversed phase with respect to that of the second sawtooth-wave generated from the second sawtooth-wave generator (7-B);
• a comparator circuit (7-D) having an input terminal IN and a comparator (IC3), for comparing the first sawtooth-wave generated from the second sawtooth-wave generator (7-B) with an analog signal inputted from the input terminal IN and for generating a first pulse of high level if the first sawtooth-wave signal is higher than the analog input signal;
• a one-short vibrator (7-F) for regularly shaping the first pulse generated from the comparator circuit (7-D) to generate a second pulse having a narrower width than that of the first pulse;
• and
• an analog switch circuit (7-E) for generating the first output (P-OUT) as an analog output having a phase identical to that of the input signal by using the second and third sawtooth-waves respectively generated from the second and third sawtooth-wave generators and a second output (N-OUT) as an analog output having phase opposite to that of the input signal.

An amplifier for inputting a PWM signal, the amplifier including:

• a rising region detector (9-B) for generating a high pulse at a rising region of the PWM signal by detecting the rising region of the PWM signal;
• a falling region detector (9-C) for generating a high pulse at a falling region of the PWM signal by detecting the falling region of the PWM signal;
• a sawtooth-wave generator (9-D) for generating a sawtooth-wave of output level by initializing with the high pulse of the rising region detector;
• a one-short vibrator (9-E) for regularly forming the high pulse of the falling region detector into a narrower pulse;
• and
• a switching circuit (9-F) for being turned on by the narrow pulse shaped in the one-short vibrator (9-E) and charging a condenser with the sawtooth-wave voltage from the sawtooth-wave generator (9-D), to thereby generate a continuous and smooth analog signal.

An amplifier for inputting a digital signal from a digital signal outputting device that processes an analog signal in a digital method and outputs digital data,

• a digital data controlling and processing unit (13-B) for analyzing the digital data including a right signal, left signal, control signal and the like to output the analyzed signals as control signals;
• a storage comparator (13-C) for storing and comparing the control signals generated from the digital data controlling and processing unit (13-B) to output a high pulse corresponding to an analog signal value;
• a one-short vibrator (13-E) for shaping a narrow pulse at the starting time of a high pulse from the storage comparator (13-C);
• a sawtooth-wave generating and resetting circuit (13-D) for generating and resetting a sawtooth-wave by a high pulse output with a data starting signal generated from the digital data controlling and processing unit (13-B);
• and
• an analog switch (13-F) for generating a continuous right and left smoothing analog signal by controlling the narrower pulse shaped in the one-short vibrator (13-E), utilizing the sawtooth-wave of the sawtooth-wave generating and resetting circuit (13-D), extracting a voltage corresponding to the sawtooth-wave and charging and maintaining the voltage at condensers C54, C56.

An amplifier comprising:

• sawtooth-wave generating means for generating the first sawtooth-wave having a frequency and amplitude greater than those of an input signal and the second sawtooth-wave having a frequency identical to that of the first sawtooth-wave and amplitude greater than that of the first sawtooth-wave;
• and
• comparison means for comparing the voltage values of the input signal with the first sawtooth-wave and outputting voltage signal of high level at the region where the voltage value of the first sawtooth-wave is greater than that of the input signal;
• and
• sample/hold means for detecting and maintaining a voltage value of the second sawtooth-wave when the voltage signal of high level is started at the comparison means.

An amplifier comprising:

• sawtooth-wave generating means for generating sawtooth-wave having a period identical to that of data included in a pulse code modulation signal;
• comparison means for comparing a value of data included in the pulse code modulation signal with a counted value produced by counting a predetermined period of a clock signal and output a high level of a voltage signal if said counted value is greater than that of data;
• and
• sample/hold means for detecting and maintaining a voltage value of the sawtooth-wave when the voltage signal of high level is started at the comparison means.