Switched power supply with voltage regulator having PWM with hysteretic loop controller and method for operating and using same

A switched power supply, comprising:

• a circuit for generating pulse width modulated control pulses to control a output voltage of said switched power supply;
• a first comparator connected to receive said output voltage on one input and a first reference voltage on another input, wherein when said output voltage exceeds said first reference voltage, an output of said first comparator changes output state;
• a second comparator connected to receive said output voltage on one input and a second reference voltage on another input, wherein when said second reference voltage exceeds said output voltage, an output of said second comparator changes output state;
• and a circuit for changing said pulse width modulated pulses to first or second width limits in response to respective changes of output states of said first and second comparators.

A method for operating a switched power supply, comprising:

• generating pulse width modulated control pulses to control on and off times of said switched power supply circuit;
• and modifying a width of said pulse width modulated control pulses to control a magnitude of said an output voltage of said switched power supply;
• changing a width of said pulse width modulated pulses to first or second width limits in response to respective changes of said output voltage beyond first and second predetermined values;
• said step of changing a width of said pulse width modulated pulses comprises:
• comparing said output voltage with a first reference voltage and generating a first control output when said output voltage exceeds said first reference voltage;
• comparing said output voltage with a second reference voltage and generating a second control output when said second reference voltage exceeds said output voltage;
• and
• changing said pulse width modulated pulses to said first or second width limits in response to respective changes of said first and second control outputs.

A method for operating a switched power supply, comprising:

• generating pulse width modulated control pulses to control on and off times of said switched power supply circuit;
• and modifying a width of said pulse width modulated control pulses to control a magnitude of said an output voltage of said switched power supply;
• wherein said generating pulse width modulated control pulses comprises:
• comparing said output voltage with a ramp wave to produce a compared waveform when said ramp wave is larger than said output voltage;
• and using said compared waveform to provide a signal containing a time width proportional to said output voltage;
• wherein said changing a width of said pulse width modulated pulses comprises:
• comparing said output voltage with a first reference voltage and generating a first control output when said output voltage exceeds said first reference voltage;
• comparing said output voltage with a second reference voltage and generating a second control output when said second reference voltage exceeds said output voltage;
• and
• changing said pulse width modulated pulses to said first or second width limits in response to respective changes of said first and second control outputs.

A mass data storage device, comprising:

• a switched power supply to provide power to an element of said mass data storage device;
• said switched power supply including:
• a switched circuit for producing an output voltage;
• a circuit for generating pulse width modulated control pulses to control on and off times of said switched circuit to control a magnitude of said output voltage;
• a circuit for changing a width of said pulse width modulated pulses to first or second width limits in response to respective changes of the output voltage of said switched power supply beyond first and second predetermined values;
• wherein said circuit for changing a width of said pulse width modulated pulses comprises:
• a first comparator connected to receive an output voltage of said switched power supply on one input and a first reference voltage on another input, wherein when said output voltage exceeds said first reference voltage, an output of said first comparator changes output state;
• a second comparator connected to receive said output voltage on one input and a second reference voltage on another input, wherein when said second reference voltage exceeds said output voltage, an output of said second comparator changes output state;
• and
• a circuit for changing said pulse width modulated pulses to said first or second width limits in response to respective changes of output states of said first and second comparators.