CS204541B1 - Source of the reference current - Google Patents

Description

The invention relates to a reference voltage source in which long-term stability and accuracy are achieved by thermally stabilizing a Zener diode.

In the circuits used up to now, a thermally compensated Zener diode was used as the reference voltage source, whose Zener voltage is slightly dependent on changes in ambient temperature. The disadvantage of such a diode is its laborious assembly of several diodes, and thus a considerable price and size.

The above disadvantages can be solved source of reference ⁰ voltage by the invention, which is characterized in that the collector and base of the first of a dual transistor is connected with the first current source to the inverting input of the reference amplifier and the noninverting input of the reference amplifier is grounded to the counter ground, the emitter of the first of a dual the transistor is connected together with one end of the first divider resistor to the reference amplifier output connected to the output terminal of the reference voltage source, the second divider resistor is connected between the counting ground and the common node of one differential amplifier input and the other end of the first divider resistor; connected together with the second power supply to the second input of the differential amplifier, the output of the differential amplifier is grounded to the ground through the heating element, which is thermally conductive connected to the double transistor systems and the emitter of the second dual transistor system is grounded to the counting ground.

This connection of a conventional dual transistor achieves a high stability of the reference voltage, independent of time and ambient temperature, with an order of magnitude reduction in power compared to a thermally compensated Zener diode, while reducing the dimensions of the reference voltage source.

The attached drawing shows the wiring of a reference voltage source according to the invention.

The collector and base of the first dual transistor system A are coupled together with the first current source 1 to the inverting input of the reference amplifier X, the non-inverting input of the reference amplifier X is grounded to ground Z, the emitter of the first dual transistor system A is connected together with one end of the first resistor. to the reference amplifier output X connected to the output terminal of the reference voltage source U, the second resistor of the divider 4 is connected between ground Z and the common node of one input of the differential amplifier Y and the other end of the first resistor of divider 3; the source of current 2 to the second input of the differential amplifier Y, the output of the differential amplifier Y is earthed to the ground by a heating element R, which is thermally conductive to the double transistor systems A and B, grounded; a zem Z.

The circuit utilizes different thermal voltage coefficients of the diode formed by the base-emitter transition of the second dual transistor system B (negative coefficient) and the Zener diode formed by the base collector-emitter transition of the first dual transistor system A (positive coefficient). The corresponding voltage of the diode and the Zener diode correspond to a certain temperature.

For the selected ratio of resistors 3 and 4 of the voltage divider, there is always only one common temperature of systems A and B, at which there is zero voltage difference at the inputs of the differential amplifier Y. If this temperature of systems A and B drops or increases, an error occurs at the inputs of the differential amplifier Y

Claims (1)

PfcEDMET A reference voltage source, characterized in that the collector and base of the first dual transistor system (A) are coupled together with the first current source (1) to the inverting input of the reference amplifier (X), the non-inverting input of the reference amplifier (X) is connected to ground. Z), the emitter of the first double transistor system (A) is connected spc'u with one end of the first divider resistor (3) to the output of the reference amplifier (X) connected to the output terminal of the reference voltage source (U); a signal that causes an increase or decrease in the heating element R is connected and the temperature deviation of systems A and B from the temperature specified by the resistance ratio 3 and 4 is compensated by increasing or decreasing the heat input from the heating element R. In this way, the temperature of the Zener diode formed by the junction of the collector base - the emitter of the first dual transistor system A, which at constant diode current means a constant Zener voltage and thus a constant output voltage of the reference voltage source. The invention can be used wherever a precise reference voltage source is needed, in recorders, analog computers and the like. BETWEEN the counting ground (Z) and the common node of one differential amplifier input (Y) and the other end of the first divider resistor (3), the base of the second dual transistor system (B) being coupled together with the second current source (2) to the second differential input the amplifier (Y), the output of which is grounded to the ground of the supply voltage (N) via the heating element (R), which is thermal conductive to the double transistor systems (A) and (B), and the emitter of the second double transistor system (B) grounded to ground (Z).