EP0190110A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Voltage convertor for telephone terminal equipment
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1986-01-20
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Granted: —
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Expires: 2006-01-20
Abstract
Abstract An apparatus for generating a constant dc output voltage from a dc input voltage having a varying magnitude comprising an inductor for storing an electrical charge and a semiconductor switch for controlling the application of the input voltage to the inductor. The apparatus further comprises an error amplifier which compares the output voltage to a reference voltage and generates an error signal voltage proportional to the difference between the two voltages. An analog voltage divider generates a control voltage proportional to the ratio of the error signal voltage to the input voltage. The control voltage is applied to a pulse width converter which controls the duty cycle of the semiconductor switch responsive to changes in the input voltage such that the output voltage remains constant.
Inventors
- 👤 Jan Hjalmar Johansson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 15:13
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
161 words
A method of obtaining an output voltage (V OUT ) with a constant magnitude from a switched voltage convertor having an input voltage (V IN ) with a varying magnitude, the convertor including a periodically opened and closed switch (38), characterized in that it comprises the steps of: comparing the magnitude of said output voltage (V OUT ) to the magnitude of a reference voltage (VREF) and generating an error signal having a magnitude (V 2 ) proportional to the difference between the magnitudes of said output voltage (V OUT ) and said reference voltage (V REF ), generating a first control signal having a magnitude ((V 3 ) proportional to the ratio of the magnitude (V 2 ) of said error signal to the magnitude of said input voltage (VIN), and generating a second control signal (V SWITCH ) to drive said switch (38) with a duty cycle proportional to the magnitude (V 3 ) of said first control signal.
Claim 2
Independent Claim
161 words
A method of obtaining an output voltage (V OUT ) with a constant magnitude from a switched voltage convertor having an input voltage (V IN ) with a varying magnitude, the convertor including a periodically opened and closed switch (38), characterized in that it comprises the steps of: comparing the magnitude of said output voltage (V OUT ) to the magnitude of a reference voltage (VREF) and generating an error signal having a magnitude (V 2 ) proportional to the difference between the magnitudes of said output voltage (V OUT ) and said reference voltage (V REF ), generating a first control signal having a magnitude ((V 3 ) proportional to the ratio of the magnitude (V 2 ) of said error signal to the magnitude of said input voltage (VIN), and generating a second control signal (V SWITCH ) to drive said switch (38) with a duty cycle proportional to the magnitude (V 3 ) of said first control signal.
Claim 3
Dependent Claim
154 words
An apparatus for carrying out the method according to claim 1 for obtaining an output voltage (V OUT ) with a constant magnitude from a switched voltage convertor having an input voltage (V IN ) with a varying magnitude, the convertor including a periodically opened and closed switch (38), characterized in that the apparatus comprises: an error circuit (50) which provides an error signal (V 2 ) proportional to the difference between said output voltage (V OUT ) and a reference voltage (V REF ), a divider circuit (70) which provides a first control signal (V 3 ) which is proportional to the ratio of said error signal (V 2 ) to said input voltage (V IN ), and a pulse width convertor circuit which provides a second control signal (V SWITCH ) to drive said switch (38) with a duty cycle proportional to the magnitude (V 3 ) of said first control signal.
Claim 4
Dependent Claim
130 words
Apparatus according to claim 2, characterized in that the divider circuit (70) comprises: a first (R 3 ) and a second (R 1 ) resistor having a substantially constant, temperature independent first resistance ratio (R 3/ R l ), a third (R 2 ) and a fourth (R O ) resistor having a substantially constant, temperature independent second resistance ratio (R 2 /R 0 ), and a temperature-stabilized reference voltage (V REF ), the magnitude (V3) of said first control signal being substantially equal to the product of said first resistance ratio (R 3 /R 1 ), said second resistance ratio (R 2 /R 0 ), said reference voltage (V REF ) and said ratio of the error signal (V 2 ) to the input voltage ( V IN ).
Claim 5
Dependent Claim
45 words
Apparatus according to claim 2 or 3, characterized in that the pulse width convertor circuit (52) comprises a voltage generator (60) for providing a linearly varying voltage, and a comparator (58) for comparing said linearly varying voltage to said first control signal (V 3 ).
References Cited (Backward Citations)
No citation records indexed.
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