US 6,982,590 B2 | ||
Bias current generating circuit, laser diode driving circuit, and optical communication transmitter | ||
Toshiki Seshita, Kanagawa (Japan) | ||
Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
Filed on Feb. 18, 2004, as Appl. No. 10/779,653. | ||
Claims priority of application No. 2003-124034 (JP), filed on Apr. 28, 2003. | ||
Prior Publication US 2005/0104652 A1, May 19, 2005 | ||
Int. Cl. G05F 1/10 (2006.01) |
U.S. Cl. 327—539 | 16 Claims |
1. A bias current generating circuit comprising:
a bandgap reference circuit connected to a high power supply voltage terminal for receiving a high power supply voltage and
a low power supply voltage terminal for receiving a low power supply voltage, and having a first output terminal for outputting
a first voltage which is constant regardless of a temperature, and a second output terminal for outputting a second voltage
which changes in accordance with a temperature;
a first low-potential-side constant-current source circuit which includes a first resistor connected between said low power
supply voltage terminal and a first terminal, and a first current path connected between said first terminal and a first current
supply terminal, receives the second voltage as a reference potential, and outputs a first electric current dependent on a
temperature and corresponding to said first resistor from said first current supply terminal;
a second low-potential-side constant-current source circuit which includes a second resistor connected between said low power
supply voltage terminal and a second terminal, and a second current path connected between said second terminal and a second
current supply terminal, receives the first voltage as a reference potential, and outputs a second electric current independent
of a temperature and corresponding to said second resistor from said second current supply terminal;
a third resistor having one end connected to said high power supply voltage terminal;
a third low-potential-side constant-current source circuit which is connected between the other end of said third resistor
and said low power supply voltage terminal, receives the first voltage as a reference potential, and supplies a temperature-independent
third electric current to said third resistor;
a high-potential-side constant-current source circuit which includes a fourth resistor connected between said high power supply
voltage terminal and a third terminal, and a third current path connected between said third terminal and a third current
supply terminal, receives a third voltage at the other end of said third resistor as a reference potential, and outputs a
fourth electric current independent of a temperature and corresponding to said fourth resistor from said third current supply
terminal; and
a current mirror circuit which is connected to said high power supply voltage terminal to receive the high power supply voltage,
and generates a bias current in accordance with an electric current supplied from a reference current terminal,
wherein said first, second, and third current supply terminals are connected to said reference current terminal.
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