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US 5,291,074 AGranted
BiCMOS track and hold amplifier
AssigneeVanguard Semiconductor, a division of CA Micro Devices
InventorMehrdad Nayebi
Life of this patent
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Abstract
A BiCMOS track and hold amplifier provides improved features of pedestal cancellation and feedthrough reduction. A further aspect of the present invention for multi-purpose functional (operational) capabilities, such as an operational amplifier, a track and hold configuration, an emitter follower, or a cable driver type configuration, based upon common architecture.
Claims13
A track and hold apparatus having a track mode and a hold mode, said track and hold apparatus comprising:
- an input stage having an input terminal for receiving an input signal;
- an output stage having an input terminal and an output terminal;
- a holding capacitor coupled to said input terminal of said output stage;
- an NMOS transistor coupled between said output terminal of said input stage and said input terminal of said output stage, said NMOS transistor turned on during said track mode and turned off during said hold mode;
- a PMOS transistor coupled between said output terminal of said input stage and ground, said PMOS transistor turned on during said hold mode and turned off during said track mode;
- and
- a switch driver for turning said NMOS and PMOS transistors on and off, said switch driver generating a single clock signal received by both said NMOS and PMOS transistors, said single clock signal turning said NMOS transistor off before turning said PMOS transistor on during transition from said track mode to said hold mode.
4 more elements
A track and hold apparatus having a track mode and a hold mode, said track and hold apparatus comprising:
- an input stage having an input terminal and an output terminal, said input terminal of said input stage for receiving an input signal, said input stage having an output impedance;
- an output stage having a first and second input terminal and an output terminal;
- a first holding capacitor coupled to said first input terminal of said output stage;
- a second holding capacitor coupled to said second input terminal of said output stage;
- a first switch coupled between said output terminal of said input stage and said first input terminal of said output stage, said first switch turned on during said track mode and turned off during said hold mode;
- a second switch coupled between said output terminal of said input stage and ground, said second switch turned on during said hold mode and turned off during said track mode;
- a circuit having an output terminal and an output impedance, said output impedance of said circuit matching said output impedance of said input stage;
- a third switch coupled between said second input terminal of said output stage and said output terminal of said circuit, said third switch turned on during said track mode and turned off during said hold mode;
- and
- a fourth switch coupled between said output terminal of said circuit and ground, said fourth switch turned on during said hold mode and turned off during said track mode.
7 more elements
A track and hold apparatus having a track mode and a hold mode, said track and hold apparatus comprising:
- a main track and hold circuit comprising:
- a first input stage having an input terminal and an output terminal, said input terminal of said first input stage for receiving an input signal;
- a first output stage having a first and a second input terminal and an output terminal;
- a holding capacitor coupled to said first input terminal of said first output stage;
- and
- a first switch coupled between said output terminal of said first input stage and said first input terminal of said first output stage, said first switch turned on during said track mode and turned off during said hold mode, said first switch creating a charge injection into said holding capacitor during transition from said track mode to said hold mode;
- and
- a dummy track and hold circuit comprising:
- a first dummy holding capacitor coupled to said second input terminal of said output stage of said main track and hold circuit;
- means for creating a dummy charge injection into said first dummy holding capacitor during transition from said track mode to said hold mode;
- a dummy inverting stage coupled between said first dummy holding capacitor and said means for creating said dummy charge injection.
8 more elements
A track and hold apparatus having a track mode and a hold mode, said track and hold apparatus comprising:
- an input buffer having an input terminal and an output terminal;
- an output buffer having an input terminal and an output terminal;
- a holding capacitor having a first terminal and a second terminal, said first terminal coupled to said input terminal of said output buffer, said second terminal coupled to ground;
- a first current source connected to said output terminal of said input buffer;
- a first current sink connected to said output terminal of said input buffer, said current sink turned on during said track mode and turned off during said hold mode;
- a second current source;
- a second current sink connected to said second current source, said current sink turned off during said track mode and turned on during said hold mode;
- a first diode connected between said second current source and said first terminal of said holding capacitor;
- a second diode connected between said first terminal of said holding capacitor and said first current sink;
- a third diode;
- and
- a feedback loop having a first terminal and a second terminal, said output terminal of said output buffer connected to said first terminal of said feedback loop, said third diode connected between said second terminal of said feedback loop and said second current source.
9 more elements
Dependencies are inferred from the claim text.