US 12,455,585 B2
Low-power reference current and voltage source circuits insensitive to temperature and voltage variations
Kang-Shuo Chang, New Taipei (TW); and Kaoru Takasuka, New Taipei (TW)
Assigned to iSentek Inc., New Taipei (TW)
Filed by Kang-Shuo Chang, New Taipei (TW); and Kaoru Takasuka, New Taipei (TW)
Filed on Jul. 31, 2023, as Appl. No. 18/361,932.
Claims priority of application No. 112124894 (TW), filed on Jul. 4, 2023.
Prior Publication US 2025/0013256 A1, Jan. 9, 2025
Int. Cl. G05F 3/16 (2006.01); G05F 1/46 (2006.01)
CPC G05F 3/16 (2013.01) [G05F 1/468 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A reference current generating circuit, comprising:
a reference voltage generating circuit configured to generate a first reference voltage according to a first current, wherein the reference voltage generating circuit comprises a native transistor device, and the first current flows through the native transistor device; and
a current source circuit coupled to the reference voltage generating circuit and configured to generate a reference current according to the first reference voltage, wherein the current source circuit comprises a cascode transistor circuit, and the reference current flows through the cascode transistor circuit,
wherein the cascode transistor circuit comprises a low-voltage transistor device and a high-voltage transistor device coupled in series,
wherein the current source circuit further comprises: a first transistor device having a first terminal, a second terminal, and a control terminal, wherein the first terminal of the first transistor device is coupled to a first voltage, the second terminal of the first transistor device is coupled to the cascode transistor circuit, and the control terminal of the first transistor device is coupled to the second terminal of the first transistor device.