ENDOSCOPE APPARATUS
An endoscope apparatus has an insertion portion having an image pickup device in a distal end portion, and a main body portion. The endoscope apparatus has a waveform shaping circuit that is provided in the distal end portion of the insertion portion, a stabilizing circuit that stabilizes a power supply voltage to the waveform shaping circuit, a load circuit that is connected to a power supply line that supplies the power supply voltage of the waveform shaping circuit, and a current drawing circuit that draws a predetermined current to the load circuit from the power supply line in response to an operation state of the waveform shaping circuit so that a potential difference between a power supply voltage of the waveform shaping circuit in a non-operation time period of the waveform shaping circuit and a power supply voltage in an operation time period of the waveform shaping circuit becomes small.
1 . An endoscope apparatus having an insertion portion having an image pickup device and a circuit in a distal end portion, and a main body portion, comprising:
a stabilizing circuit that stabilizes a power supply voltage to the circuit;
a load circuit that is connected to a power supply line that supplies the power supply voltage of the circuit; and
a current drawing circuit that draws a predetermined current to the load circuit from the power supply line in response to an operation state of the circuit so that a potential difference between a power supply voltage in a non-operation time period of the circuit and a power supply voltage in an operation time period of the circuit becomes small.
2 . The endoscope apparatus according to claim 1 ,
wherein the circuit is a waveform shaping circuit that shapes a waveform of a drive signal to the image pickup device.
3 . The endoscope apparatus according to claim 1 ,
wherein the current drawing circuit draws the predetermined current to the load circuit so that the power supply voltage in the non-operation time period of the circuit and the power supply voltage in the operation time period of the circuit become equal.
4 . The endoscope apparatus according to claim 1 ,
wherein the load circuit is provided in the main body portion.
5 . The endoscope apparatus according to claim 2 ,
wherein the load circuit is provided in the main body portion, and
the current drawing circuit performs drawing of the predetermined current from the power supply line by drawing the predetermined current to the load circuit via a line connected to a connection point to the power supply line in the distal end portion of the waveform shaping circuit.
6 . The endoscope apparatus according to claim 1 ,
wherein the load circuit is provided in the distal end portion.
7 . The endoscope apparatus according to claim 1 ,
wherein the load circuit has a light emitting element.
8 . The endoscope apparatus according to claim 7 ,
wherein the light emitting element is provided in the main body portion, and
the endoscope apparatus further comprises a light guide for emitting emission light of the light emitting element from the distal end portion.
9 . The endoscope apparatus according to claim 7 ,
wherein the light emitting element is provided in the distal end portion.
10 . The endoscope apparatus according to claim 7 ,
wherein the load circuit and the light emitting element are provided in the distal end portion.
11 . An endoscope apparatus having an insertion portion having an image pickup device in a distal end portion, and a main body portion, comprising:
a variable voltage source in the main body portion,
wherein the variable voltage source changes a power supply voltage in response to an operation state of the distal end portion so that a potential difference of power supply voltages before and after change of an operation of the distal end portion becomes small.
12 . The endoscope apparatus according to claim 11 ,
wherein the variable voltage source changes the power supply voltage in response to the operation state of the distal end portion so that the power supply voltages become equal before and after the change of the operation of the distal end portion.
13 . The endoscope apparatus according to claim 12 , further comprising:
a circuit that is provided in the distal end portion; and
a stabilizing circuit that stabilizes a power supply voltage to the circuit,
wherein the variable voltage source changes the power supply voltage to the circuit in response to an operation state of the circuit.
14 . The endoscope apparatus according to claim 13 ,
wherein the circuit is a waveform shaping circuit that shapes a waveform of a drive signal to the image pickup device.
15 . The endoscope apparatus according to claim 13 ,
wherein the variable voltage source reduces the power supply voltage which is supplied to the circuit during a non-operation time period of the circuit so that the power supply voltage in the non-operation time period of the circuit and the power supply voltage in an operation time period of the circuit become equal.
16 . The endoscope apparatus according to claim 11 , further comprising:
a light emitting element that is connected to the variable voltage source.
17 . The endoscope apparatus according to claim 16 ,
wherein the light emitting element is provided in the main body portion, and
the endoscope apparatus further comprises a light guide for emitting emission light of the light emitting element from the distal end portion.
18 . The endoscope apparatus according to claim 14 ,
wherein the variable voltage source includes a constant voltage source and a light emitting element, and reduces the power supply voltage which is supplied to the waveform shaping circuit by controlling connection of the constant voltage source and the light emitting element.