Drive circuit for an infrared remote control transmitter

Claim 2

In an infrared remote control transmitter for controlling a television system, apparatus comprising: a reference circuit point for receiving a reference potential; a supply circuit point for receiving a DC supply voltage; a battery connected with a predetermined polarity connected between said supply and reference circuit points; at least one light-emitting diode for emitting infrared radiation when rendered conductive, said light emitting diode having a cathode and an anode, one of said cathode and anode being connected to said reference circuit point, said light-emitting diode being poled with respect to said reference circuit point so as to be conductive in response to the application of a voltage to the other one of said cathode and anode having the opposite polarity to said battery with respect to said reference circuit point and non-conductive in response to the application of a voltage to said other one of said cathode and anode having the same polarity as said battery with respect to said reference circuit point; a source circuit point for receiving an input signal having pulses encoded to represent information for controlling a predetermined function of said television receiver; a drive circuit point; a capacitor directly connected between said drive circuit point and said other one of said cathode and anode; a diode directly connected between said other one of said cathode and anode and said reference circuit point and poled in the opposite sense to said light-emitting diode with respect to said reference circuit point; push-pull amplifier means for developing a drive voltage at said drive point including first and second bipolar transistors of opposite conduction types, each of said transistors having a collector-emitter path and a base electrode for controlling the conduction of said collector-emitter path, said collector-emitter path of said first transistor being directly connected between said supply circuit point and said drive circuit point, said collector-emitter path of said second transistor being connected between said drive circuit point and said reference point; and input means coupled between said source circuit point and said bases of said first and second transistors for rendering said collector-emitter path of said first transistor conductive and said collector-emitter path of said second transistor non-conductive in response to a first portion of said pulses of said input signal and for rendering said collector-emitter path of said second transistor conductive and said collector-emitter path of said first transistor non-conductive in response to a second portion of said pulses of said input signal.

Claim 3

The apparatus recited in claim 1 wherein: three light-emitting diodes poled in the same direction are connected in series between said capacitor means and said reference circuit point.

Claim 4

The apparatus recited in claim 1 wherein: a second capacitor is directly connected between said drive point and said other one of said cathode and anode in parallel with said first mentioned capacitor directly connected between said drive point and said other one of said cathode and anode.

Claim 5

The apparatus recited in claim 1 wherein: said input means includes a first capacitor connected between said source circuit point and said base of said first transistor; first means connected between said supply circuit point and said base of said first transistor for discharging said first capacitor; a second capacitor connected between said source circuit point and said base of said second transistor; and second means connected between said base of said second transistor and said reference circuit point for discharging said second capacitor.

Claim 6

The apparatus recited in claim 4 wherein: said first means includes a further diode poled to be conductive when said collector-emitter path of said first transistor is non-conductive and non-conductive when said collector-emitter path of said first transistor is conductive; and said second means includes a still further diode poled to be conductive when said collector-emitter path of said second transistor is non-conductive and non-conductive when said collector-emitter path of said second transistor is conductive.

Claim 7

In an infrared remote control transmitter for controlling a television system, apparatus comprising: a reference circuit point for receiving a reference potential; a supply circuit point for receiving a DC supply voltage; a battery connected with a predetermined polarity connected between said supply and reference circuit points; three light-emitting diodes which emit infrared radiation when rendered conductive directly connected in series between a voltage application circuit point and said reference circuit point, all of said light-emitting diodes being poled with respect to said reference circuit point so as to be conductive in response to the application of a voltage to said voltage application circuit point having the opposite polarity to said battery with respect to said reference circuit point and non-conductive in response to the application of a voltage to said voltage application circuit point having the same polarity as said battery with respect to said reference circuit point; a source circuit point for receiving an input signal having pulses encoded to represent information for controlling a predetermined function of said television receiver; a drive circuit point; a first capacitor directly connected between said drive circuit point and said voltage application circuit point; a second capacitor directly connected between said drive circuit point and said voltage application circuit point; a diode directly connected between said voltage application circuit point and said reference circuit point and poled in the opposite sense to said light-emitting diode with respect to said reference circuit point; push-pull amplifier means for developing a drive voltage at said drive point including first and second bipolar transistors of opposite conduction types, each of said transistors having a collector-emitter path and a base electrode for controlling the conduction of said collector-emitter path, said collector-emitter path of said first transistor being directly connected between said supply circuit point and said drive circuit point, said collector-emitter path of said second transistor being connected between said drive circuit point and said reference point; and input means coupled between said source circuit point and said bases of said first and second transistors for rendering said collector-emitter path of said first transistor conductive and said collector-emitter path of said second transistor non-conductive in response to a first portion of said pulses of said input signal and for rendering said collector-emitter path of said second transistor conductive and said collector-emitter path of said first transistor non-conductive in response to a second portion of said pulses of said input signal.

Claim 8

In an infrared remote control transmitter for controlling a television system, apparatus comprising: a reference circuit point for receiving a reference potential; a supply circuit point for receiving a DC supply voltage; a battery connected with a predetermined polarity connected between said supply and reference circuit points; three light-emitting diodes which emit infrared radiation when rendered conductive directly connected in series between a voltage application circuit point and said reference circuit point, all of said light-emitting diodes being poled with respect to said reference circuit point so as to be conductive in response to the application of a voltage to said voltage application circuit point having the opposite polarity to said battery with respect to said reference circuit point and non-conductive in response to the application of a voltage to said voltage application circuit point having the same polarity as said battery with respect to said reference circuit point; a source circuit point for receiving an input signal having pulses encoded to represent information for controlling a predetermined function of said television receiver; a drive circuit point; a first capacitor directly connected between said drive circuit point and said voltage application circuit point; a second capacitor directly connected between said drive circuit point and said voltage application circuit point; a diode directly connected between said voltage application circuit point and said reference circuit point and poled in the opposite sense to said light-emitting diode with respect to said reference circuit point; push-pull amplifier means for developing a drive voltage at said drive point including first and second bipolar transistors of opposite conduction types, each of said transistors having a collector-emitter path and a base electrode for controlling the conduction of said collector-emitter path, said collector-emitter path of said first transistor being directly connected between said supply circuit point and said drive circuit point, said collector-emitter path of said second transistor being connected between said drive circuit point and said reference point; and input means coupled between said source circuit point and said bases of said first and second transistors for rendering said collector-emitter path of said first transistor conductive and said collector-emitter path of said second transistor non-conductive in response to a first portion of said pulses of said input signal and for rendering said collector-emitter path of said second transistor conductive and said collector-emitter path of said first transistor non-conductive in response to a second portion of said pulses of said input signal.