Patent ID: 7091787

Claim:
A transconductance amplifier comprising: a first voltage source; an operational amplifier coupled to said first voltage source; a first NPN transistor and a first PNP transistor coupled to an output of said operational amplifier, said first NPN transistor and said first PNP transistor coupled back to back; a first resistor coupled to the emitters of said first NPN transistor and said first PNP transistor; a second PNP transistor, said second PNP transistor diode coupled to said first NPN transistor; a third PNP transistor, said third PNP transistor forming a current mirror with said second PNP transistor; a fourth PNP transistor, said fourth PNP transistor coupled to the emitters of said second PNP transistor and said third PNP transistor, said fourth PNP transistor further comprising a second resistor and a third resistor, said second resistor and said third resistor parallel-connected to the base of said fourth PNP transistor; a second voltage source coupled to said second PNP transistor, said third PNP transistor, and said fourth PNP transistor; a second NPN transistor, said second NPN transistor diode coupled to said first PNP transistor; a third NPN transistor, said third NPN transistor forming a current mirror with said second NPN transistor; a fourth NPN transistor, said fourth NPN transistor coupled to the emitters of said second NPN transistor and said third NPN transistor, said fourth NPN transistor further comprising a fourth resistor and a fifth resistor, said fourth resistor and said fifth resistor parallel-connected to the base of said fourth NPN transistor; and a third voltage source coupled to said second NPN transistor, said third NPN transistor and said fourth NPN transistor.