A solid-state image sensor has a pixel array including pixel units and column signal lines. Each pixel unit includes a photoelectric converter and an amplifier transistor which outputs a signal to the column signal line. The sensor includes a cascode current source which supplies a current to the amplifier transistor and which includes cascode-connected first and second transistors, a first bias circuit which determines a voltage of a first node connected to a gate of the first transistor, and a second bias circuit which determines a voltage of a second node connected to a gate of the second transistor.

Solid-state image sensor and camera

The invention discloses the low-power-source-dependency band-gap reference voltage circuit design based on the PTAT current. The low-power-source-dependency band-gap reference voltage circuit design comprises a starting circuit, a reference voltage generating circuit and a reference buffering output circuit, wherein the reference voltage generating circuit is composed of three parts including a cascode current mirror circuit, a positive temperature coefficient PTAT current generating circuit and a negative temperature coefficient current generating circuit. The starting circuit is used for starting the reference voltage generating circuit after being powered on. The reference buffering circuit is used for reducing the output resistance to drive a low-resistance load and meanwhile providing various voltage references. According to the low-power-source-dependency band-gap reference voltage circuit design based on the PTAT current, the cascode PTAT current generating circuit is used for being coordinated with an external circuit to generate the reference voltage with the stable performance and the zero temperature coefficient, and meanwhile the method of separating an external power source from the bias voltage required by the circuit is used for greatly reducing the power source dependency caused by the channel length modulation effect of an MOS device.

Low-power-source-dependency band-gap reference voltage circuit design based on PTAT current

The invention discloses a cascode fully integrated low-dropout linear voltage regulator circuit. According to the invention, a ascode current source is introduced to replace a conventional single transistor current source in a Cascoded Flipped Voltage Follower-Low-dropout (CAFVF-LDO) circuit, which increases the loop gain of the CAFVF-LDO circuit under heavy load condition; at the same time based on the structure features of the Cascode Current Source (CCS), a cascode compensation technology is introduced. Compared with the conventional CAFVF-LDO, the circuit of the invention, by means of a very small on chip compensation capacitor, realizes stable operation under a much lower load current, and a cascode compensation capacitor also expands the Unity-Gain-Frequency (UGF) of the LDO circuit under heavy load condition, and further improves load transient response of the circuit. The cascode fully integrated low-dropout linear voltage regulator circuit can be widely applied to the field of integrated circuits.

Cascode fully integrated low-dropout linear voltage regulator circuit

Systems and methods for voltage regulation provide close-tolerance voltage regulation over a wide input voltage range. A voltage regulator has a reference voltage unit, first and second transistors, and an active circuit element. The reference voltage unit is configured to provide a substantially constant voltage signal at a reference node. The first transistor is coupled to the reference node and to an input node having an input voltage. The active circuit element is coupled to the first transistor. The second transistor has a source coupled in feedback configuration to a first input of the active circuit element, a drain coupled to the input node, and a gate configured to be driven by the active circuit element to force the source to a voltage about equal to a voltage of a second input of the active circuit element independent of the input voltage.

System and method for voltage regulation

System and method for voltage regulation using feedback to active circuit element

A cascode current mirror circuit and a bandgap circuit are provided. The circuits are used together and function as a reference voltage circuit. The reference voltage circuit outputs a reference current resistant to temperature variation and ripple-voltage. Accordingly, a voltage stabilizing/regulating circuit corrects error voltage precisely and promptly, and the resultant voltage is temperature insensitive and ripple-voltage-independent.

Cascode current mirror circuit, bandgap circuit, reference voltage circuit having the cascode current mirror circuit and the bandgap circuit, and voltage stabilizing/regulating circuit having the reference voltage circuit

Chi En Liu

Papers

Cascode current mirror circuit, bandgap circuit, reference voltage circuit having the cascode current mirror circuit and the bandgap circuit, and voltage stabilizing/regulating circuit having the reference voltage circuit