The invention discloses a soft start device that can realize
linear control, which comprises a working circuit, a soft start circuit and a start
control circuit; the working circuit comprises a DC power source, a load
capacitance, a power tube and a feedback circuit which are connected between the DC power source and the load
capacitance and also a soft start circuit and a start
control circuit, and the power tube is provided with a control end; the soft start circuit comprises a
voltage generator, the output
voltage of which is increased gradually after start, and an
error amplifier, the input end of which is connected with the output end of the
voltage generator; the input end of the
error amplifier is connected between the output end of the power tube and the ground, while the output end of the
error amplifier is connected to the control end of the power tube; when the start
control circuit detects that the start begins, the soft start circuit is set to be in normal working state and a feedback circuit is set to be in off working state. The adoption of the device of the invention can avoid surge current at the moment when the power source charges the load
capacitance at the instance when the circuit is electrified, can repeatedly use the existing error
amplifier in the original circuit structure and save the areas and
energy consumption of chips.