Transducer apparatus and methods
AssigneeCirrus Logic, Inc.
InventorIan Johnson Smith
Life of this patent
Estimating the term…
Abstract
This application relates to transducer apparatus (300, 400), especially for MEMS capacitive transducers. The apparatus has a voltage bias generator (102) for receiving a supply voltage (VDD) and generating a bias voltage (VB) for biasing a capacitive transducer (101). A voltage supply path extends between a supply voltage input terminal (309a) and the voltage bias generator (102). A programmable trim circuit (207), in use, controls the bias voltage generated by the voltage bias generator. A first filter (301) is configured to applying filtering to the voltage supply path. A programming contact pad (308) is configured to form an external contact of the transducer apparatus when packaged and is electrically coupled to the programmable trim circuit via a signal path that does not include the first filter.
Claims18
A capacitive sensing transducer apparatus comprising:
- a voltage bias generator for receiving a supply voltage and generating a bias voltage for biasing a capacitive sensing transducer;
- a voltage supply path between a supply voltage input terminal and the voltage bias generator;
- a programmable trim circuit for, in use, controlling the bias voltage generated by the voltage bias generator;
- a first filter configured to applying filtering to the voltage supply path;
- and
- a programming contact pad that is electrically coupled to the programmable trim circuit via a signal path that does not include the first filter, the programming contact pad being configured to form an external contact of the capacitive sensing transducer apparatus when packaged;
- wherein:
- the programming contact pad is electrically coupled to the voltage supply path at a node between the first filter and the voltage bias generator;
- and
- the programmable trim circuit is electrically coupled to the voltage supply path between the first filter and the voltage bias generator.
A capacitive sensing transducer apparatus comprising:
- a package structure;
- an integrated circuit die within the package structure;
- wherein the integrated circuit die comprises:
- a voltage bias generator for receiving a supply voltage and generating a bias voltage for biasing a capacitive transducer;
- and
- a programmable trim circuit for, in use, controlling the bias voltage generated by the voltage bias generator;
- and
- wherein the voltage bias generator and programmable trim circuit are both electrically coupled to a first die contact on said integrated circuit die;
- a first filter formed within the package structure on a first substrate separate to said integrated circuit die, the first filter comprising a filter resistor in series in a voltage supply path between a voltage supply terminal of the first substrate and the first die contact;
- and
- a programming contact pad forming an external electrical contact of the packaged structure, the programming contact pad being electrically coupled to a node of the voltage supply path between the filter resistor and the first die contact such that there is a signal path between the programming contact pad and the programmable trim circuit and wherein the signal path does not include said first filter.
Dependencies are inferred from the claim text.