| 摘要 |
The low-voltage supply, which is voltage-controlled, is designed to give on the basis of an external supply voltage (Vcc), which can vary between two values (Vccmin, Vccmax), an output voltage (Vout) stabilized with respect to the temperature of functioning, the value of external supply voltage, and the manufacturing method. The device comprises a reference voltage generator (1), which is subjected to the external supply voltage (Vcc) and outputs a reference voltage (Vref), low and controlled, whose value is below that of the minimum value (Vccmin) of external supply voltage, and at least a second voltage generator (2) connected in cascade with the reference voltage generator (1). The second voltage generator (2) is designed to give the output voltage (Vout), whose value is constant and substantially higher than that of the input reference voltage (Vref), and a current (lout) of determined value, which is directed to a constant current source of differential amplifier. The second voltage generator (2) comprises an operational amplifier (3), whose first input (E1) is connected directly to the output of reference voltage generator (1), and the output (S1) connected by a feedback circuit comprising resistors (R'1, R'2) to the second input (E2) of operational amplifier. The reference voltage generator (1) is an electronic circuit of bandgap type. An electronic circuit of low power such as a differential amplifier connected as a load also requires a third voltage generator, which is connected in parallel with the second voltage generator, for the provision of biasing voltage, and comprises a constant current source with two MOS transistors. The third voltage generator outputs a voltage which is below that of the second voltage generator, and the difference between two voltages is sufficiently close to the threshold voltage of transistor in the constant current source. The third voltage generator has a structure analogous to that of the second voltage generator.
|
