Seiko Epson Corporation

Ryo Ichikawa

Hisahiro Ito

Akio Tsutsumi

Yasunari Furuya

There is configured a charge pump circuit for outputting a phase difference current to a first node, the charge pump circuit including a first current source coupled between a high potential power supply node and the first node, a second current source coupled between a low potential power supply node and the first node, a first switch coupled between the first current source and the first node, a second switch coupled between the second current source and the first node, a third switch coupled between the first current source and a second node, a fourth switch coupled between the second current source and the second node, a third current source for supplying a negative offset current to the first node, and a push-type differential amplifier circuit an input side of which is coupled to the first node, and an output side of which is coupled to the second node.

Charge pump circuit, PLL circuit, and oscillator

A charge pump includes: a switch circuit that switches a current source conducted to an output node based on a signal from a phase frequency detector included in a PLL circuit; a first current source that is the current source provided between a high potential node and the switch circuit, and supplies a current to the output node by a first conduction-type depletion mode MOS transistor forming a self-bias circuit; and a second current source that is the current source provided between a low potential node and the switch circuit, and draws the current from the output node by the first conduction-type depletion mode MOS transistor forming the self-bias circuit.

Growing community of inventors

Minowa, Japan

Ryo Ichikawa