US 5,675,240 AGranted

All digital switching regulator for use in power supplies, battery chargers, and DC motor control circuits

AssigneesMitsubishi Electric Semiconductor Software Co., Ltd., Mitsubishi Denki Kabushiki Kaisha

InventorsYukio Fujisawa, Isao Takinoue

Life of this patent

Estimating the term…

Loading patent…

Abstract

A switching regulator is composed of digital circuits only. A switching regulator (30) comprises a driver (2) for directly controlling the operation of a switching transistor (1), and an OR gate (6) for determining the logic issued by the driver (2). An output terminal (Q) of an RS flip-flop (5) is connected to one input end of the OR gate (6), the output of a timer (40c) is applied to a set terminal (S) of the RS flip-flop (5), and the output of a comparator (4) is applied to a reset terminal (R1) through an OR gate (7). At a non-reverse input end of the comparator (4), a reference voltage (VE) is applied by a D/A convertor (40b), while a feedback voltage (VFB) is applied to a reverse input end. Accordingly, chopping of the switching transistor (1) is done on the basis of a rectangular pulse.

Claims18

Dependent claims

A switching regulator comprising:

a first logic circuit including:
a set end provided with a series of rectangular pulses from a pulse source, each pulse transiting between complementary first and second logic values,
a reset end, and
an output end issuing said first logic value when said first logic value is applied to said set end and said second logic value when said first logic value is applied to said reset end;
a second logic circuit including:
a first input end provided with a fixed value,
a second input end provided with a variable value to be measured, and
a second output end connected to said reset end of said first logic circuit and issuing said first logic value when the variable value applied to said second input end is greater than said fixed value applied to said first input end and said second logic value when said variable value applied to said second input end is smaller than said fixed value applied to said first input end;
and
a third logic circuit including a first input end connected to said output end of said first logic circuit, a second input end provided with said series of rectangular pulses, and a third output end issuing an OR logic value relative to logic values applied at said first and second input ends of said third logic circuit.

7 more elements

A power source circuit comprising:

an output terminal and an input terminal to which an input voltage is supplied;
a switching element including a first end connected to said input terminal, a second end connected to said output terminal, and a control end, said switching element being controlled to connect said first end and said second end on the basis of a control value applied to said control end by a control element;
a first logic circuit including:
a set end provided with a series of rectangular pulses from a pulse source, each pulse transiting between complementary first and second logic values,
a resent end, and
a first output end connected to said control end of said switching element, said first output end issuing said first logic value when said first logic value is applied to said set end and said second logic value when said first logic value is applied to said reset end;
a second logic circuit including:
a first input end provided with a fixed value,
a second input end provided with a variable value indicating a voltage being applied to said output terminal, and
a second output end connected to said reset end of said first logic circuit, said second output end issuing said first logic value when the variable value applied to said second input end is greater than said fixed value applied to said first input end and said second logic value when said variable value applied to said second input end is smaller than said fixed value applied to said first input end;
a smoothing circuit provided between said second end of said switching element and said output terminal;
and
a resonance detecting circuit detecting when the smoothing circuit is resonating at a frequency of said series of rectangular pulses.

10 more elements

A battery charger control circuit comprising:

an input terminal to which an input voltage is supplied and an output terminal for supplying a charging current to a battery;
a switching element including a first end connected to said input terminal, a second end connected to said output terminal, and a control end, said switching element being controlled to connect said first end and said second end on the basis of a control value applied to said control end;
current-voltage converting means for converting said charging current into a voltage;
measured value generating means for generating a measured value on the basis of a voltage applied to said battery;
reference signal generating means for providing a reference value to be compared with said measured value;
and
a microcomputer including:
a timer supplying a series of rectangular pulses, each pulse transiting between complementary first and second logic values,
a first logic circuit including:
a set end provided with said series of rectangular pulses,
a reset end, and
a first output end connected to said control end of said switching element, said first output end issuing said first logic value when said first logic value is applied to said set end and said second logic value when said first logic value is applied to said reset end,
a second logic circuit including:
a first input end provided with a fixed value,
a second input end provided with an output of said current-voltage converting means, and
a second output end issuing said first logic value when the value applied to said second input end of said second logic circuit is greater than the fixed value applied to said second input end of said second logic circuit and said second logic value when said value applied to said second input and of said second logic circuit is smaller than said fixed value applied to said first input end of said second logic circuit,
a third logic circuit including:
a first input end provided with said reference value,
a second input end provided with said measured value, and
a third output end issuing said first logic value only when a specified potential difference is detected between said first and second input ends of said third logic circuit,
a fourth logic circuit including:
a first input end connected to said second output end of said second logic circuit,
a second input end connected to said third output end of said third logic circuit, and
a fourth output end connected to said reset end of said first logic circuit, said fourth output end issuing an OR logic value relative to the logic values applied to said first and second input ends of said fourth logic circuit,
a CPU for controlling an operation of said timer, and
a data bus for mutually connecting said timer and said CPU.

23 more elements

A DC motor control circuit comprising:

an input terminal to which an input voltage is supplied and an output terminal for supplying a driving current to a DC motor;
a switching element possessing a first end connected to said input terminal, a second end connected to said output terminal, and a control end, said switching element being controlled to connect said first end and said second end on the basis of a control value applied to said control end by a control element;
current-voltage converting means for converting said driving current into a voltage;
a microcomputer including:
a timer supplying a series of rectangular pulses, each pulse transiting between complementary first and second logic values,
a first logic circuit including:
a set end provided with said series of rectangular pulses,
a reset end, and
a first output end connected to said control end of said switching element, said first output end issuing said first logic value when said first logic value is applied to said set end and said second logic value when said first logic value is applied to said reset end,
a second logic circuit including:
a first input end provided with a fixed value,
a second input end provided with an output of said current-voltage converting means, and
a second output end connected to said reset end of said first logic circuit, said second output end issuing said first logic value when the value of the current-voltage converting means output applied to said second input end of said second logic circuit is greater than the fixed value applied to said first input end of said second logic circuit, and said second logic value when said value of the current-voltage converting means output applied to said second input end of said second logic circuit is smaller than said fixed value applied to said first input end of said second logic circuit,
a CPU for controlling the operation of said timer, and
a data bus for mutually connecting said timer and said CPU.

12 more elements

Dependencies are inferred from the claim text.