| 摘要 |
PURPOSE:To start stably a band gap reference by turning on a start transistor (TR) at power application so as to supply forcibly a start current to the band gap reference and turning off the TR after the circuit reaches the steady-state. CONSTITUTION:When a constant voltage Vref is not generated on a line l1, a bias voltage Va is fed to a start TR Q11, which is turned on and a TR Q14 is turned on. Thus, the voltage level of the line l1 rises gradually from the voltage level turning of the TR Q11, and since the bias voltage Va is 1.4V, the TR Q11 is turned on. When the voltage of the line l1 rises and the sum of a collector-emitter voltage Vcd of the TR Q2 and the voltage drop across a resistor R3 is 0.7V or over, a bias voltage is given to a TR Q3, which is turned on. When the TR Q3 is saturated, the voltage level of the line l1 is a constant voltage Vref (nearly 1.2V) and the TR Q11 is turned off. |
