detection circuit

Abstract

A circuit detects a characteristic of an accessory detachably connected thereto via the multi-pole connector. The circuit has first, second and third terminals for coupling to respective first, second and third electrodes of said connector, and has an output for providing an estimate from which a characteristic of the accessory may be deduced . In the circuit, a first current source circuit is coupled to the first circuit terminal for providing a first current. The switch network includes first, second, third and fourth switch network terminals, the first switch network terminal is coupled to a reference potential, the second switch network terminal is coupled to the second circuit terminal, and the first A three-switch network terminal is coupled to the third circuit terminal. A comparator circuit provides a comparison signal, a first input terminal of which is coupled to said first circuit terminal. A second current source circuit having a monitor node coupled to the second comparator input terminal and an output node coupled to the fourth switch network terminal provides a second current to the switch network. At least one of the first current source circuit and the second current source circuit varies the first current or the second current in response to a digital control word. providing control logic for operatively controlling the interconnection state of said switch network for adjusting said digital control word in response to said comparison signal until the voltage at said first circuit terminal is equal to that at said monitor node and for supplying the regulated digital control word associated with the state of the interconnection to the output as an estimate.

Description

technical field [0001] The present invention relates to a detection circuit and more particularly to a circuit for detecting a characteristic of a device connected to the circuit. Background technique [0002] It is known to provide electronic devices such as mobile phones, tablet computers, recorded music playback devices etc. with accessory devices such as headphones. [0003] In many cases, accessory devices may be provided with electronics, so there should be no intercompatibility issues. However, in the case of accessory devices such as headphones, the user may wish to use a single accessory device with multiple electronic devices or different accessory devices with a given electronic device, and then need to ensure that each electronic device can communicate with the currently connected accessory device. Operationally Compatible. [0004] Many headphones are provided with four conductors, that is, four electrodes, and plugs that can be inserted into four conductors, ...

AI Technical Summary

Problems solved by technology

[0003] In many cases, accessory equipment can be provided wit

Images