Avalanche photodiode quenching circuit wtih resetting means having a second amplifier

US5194727A · kind A · utility

Assignee

• The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland · GB

Inventors

• Martin R. Johnson · Piedmont, US
• Robin Jones · Malvern, GB

Key dates

• Filing date: Feb 20, 1992
• Grant date: Mar 16, 1993
• Expiry date: Feb 20, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G01J2001/4466
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An avalanche photodiode quenching circuit (20) incorporates an avalanche photodiode (APD) (22) and a first comparator (C1) responsive to reduction in APD voltage. The comparator (C1) is arranged to activate an APD quench circuit (38) in response to APD avalanche initiation. The circuit (20) also includes a second comparator (C2) arranged to reset the first comparator input (N2) in response to a further reduction in APD voltage caused by initiation of quenching. The second comparator (C2) is also connected to a monostable circuit (48) arranged to latch the first comparator output response to resetting. The monostable circuit (48) maintains the first comparator output level constant until the APD (22) has recharged.