Invention Grant
- Patent Title: Dual-PFD feedback delay generation circuit
-
Application No.: US15715151Application Date: 2017-09-25
-
Publication No.: US10439620B2Publication Date: 2019-10-08
- Inventor: Theertham Srinivas , Jagdish Chand Goyal , Peeyoosh Mirajkar
- Applicant: TEXAS INSTRUMENTS INCORPORATED
- Applicant Address: US TX Dallas
- Assignee: TEXAS INSTRUMENTS INCORPORATED
- Current Assignee: TEXAS INSTRUMENTS INCORPORATED
- Current Assignee Address: US TX Dallas
- Agent Andrew Viger; Charles A. Brill; Frank D. Cimino
- Priority: IN201641032526 20160923
- Main IPC: H03L7/087
- IPC: H03L7/087 ; H03L7/197 ; H03L7/193

Abstract:
A dual-PFD circuit with delay feedback generated by a dual-modulus prescaler based on mode control from a feedback delay generation circuit. The PFD circuit can be used with a PLL feedback divider to divide a VCO clock signal VCO_clk and generate FB and FB_DLY signals. The PLL feedback divider includes a dual modulus prescaler to selectively divide the VCO_clk by either M or M+1 (such as 4/5) based on a divide mode control input to generate a prescaled divide signal, and a programmed counter/divider (N counter/1/N divider) to selectively divide the prescaled divide signal to generate the FB signal, and a delay generation circuit to selectively delay the FB signal by a pre-defined delay to generate the FB_DLY signal. The prescaler is responsive to the pre-defined delay from the delay generation circuit to change divide modes. The dual PFD circuit response to the FB and FB_DLY signals in relation to a reference signal to generate a phase comparison signal. the dual-PFD circuit can be used with a charge-pump coupled to the dual PFD circuit, and responsive the phase comparison signal to generate a frequency tuning voltage, for input to a VCO for generating the VCO clock signal. The dual PFD circuit, charge pump and VCO can be used in a PLL frequency synthesizer.
Public/Granted literature
- US20180091157A1 DUAL-PFD FEEDBACK DELAY GENERATION CIRCUIT Public/Granted day:2018-03-29
Information query
IPC分类: