CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 USC 119(a) of Korean Patent Application No. 10-2019-0080122 filed on Jul. 3, 2019 and Korean Patent Application No. 10-2019-0126404 filed on Oct. 11, 2019 in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes.

BACKGROUND

1. Field

The present disclosure relates to a sensing device with a fingerprint sensor.

2. Description of Related Art

Typically, it is beneficial for wearable devices to have a thinner, simpler and cleaner design. Accordingly, existing mechanical switches are being utilized less, in view of the implementation of dustproof and waterproof technologies and the development of models with a smooth design and a sense of design unity.

Currently, technologies such as a touch on metal (ToM) technology for touching an upper portion of a metal, a capacitor sensing technique that utilizes a touch panel, a micro-electro-mechanical-system (MEMS), and a micro strain gauge are being developed. Furthermore, the force touch function is being developed.

With regard to existing mechanical switches, a relatively large amount of size and space may be needed internally to implement switching functions, and further, and the design may not be neat due to the appearance of external protrusions or a structure that is not integrated with an external case, and a large space may be needed.

Additionally, there is a risk of electric shocks if direct contact is made with the electrically connected mechanical switch, and dust-proofing and waterproofing may be difficult to implement in view of to the structure of the mechanical switch.

Additionally, it may be beneficial to implement a touch input to be sensed with an existing fingerprint sensor.

SUMMARY

This Summary is provided to introduce a selection of concepts in simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In a general aspect, a sensing device includes a sensor, a touch input pattern included in the sensor, an oscillation circuit connected to the touch input pattern, and configured to change a capacitance of the oscillation circuit when a touch occurrence is sensed by the touch input pattern, and generate an oscillation signal based on the change in the capacitance, and a detection circuit configured to detect the touch occurrence based on a frequency included in the oscillation signal and generate a detection signal.

The oscillation signal may be input to the operation detection circuit from the oscillation circuit.

The sensor may be a fingerprint sensor.

The touch input pattern may be a conductor pattern that includes a portion of a plurality of fingerprint recognition patterns included in the fingerprint sensor.

The touch input pattern may be a conductor pattern that is disposed separately from a plurality of fingerprint recognition patterns included in the fingerprint sensor.

The oscillation circuit may include an inductance circuit including a coil element disposed on an external surface of the fingerprint sensor; and a capacitance circuit disposed on the external surface of the fingerprint sensor, and may include a capacitor device spaced apart from the coil element.

The capacitance circuit may include a capacitance that is varied by the touch occurrence that is sensed by the touch input pattern.

The oscillation circuit may include an inductance circuit including a coil element embedded in the fingerprint sensor; and a capacitance circuit including a capacitor device disposed on an external surface of the fingerprint sensor.

The capacitance circuit may include a capacitance that is varied by the touch occurrence that is sensed by the touch input pattern.

The operation detection circuit may include a frequency digital converter configured to convert the generated oscillation signal into a count value; and a touch detection circuit configured to detect the touch occurrence based on the count value input from the frequency digital converter, and generate a detection signal.

The frequency digital converter may be configured to generate the count value by counting a reference clock signal based on the oscillation signal.

The frequency digital converter may be configured to divide a reference frequency signal by using a reference frequency division ratio to generate a divided reference clock signal, divide the generated oscillation signal by using a sensing frequency division ratio, and count the divided reference clock signal by using the divided oscillation signal to generate the count value.

The frequency digital converter may include a frequency down converter configured to receive a reference frequency signal as a reference clock signal and divide the reference clock signal by using a reference frequency division ratio to generate the divided reference clock signal, a periodic timer configured to receive the oscillation signal as a sample clock signal, and generate a period counting value by counting one cycle time of the divided reference clock signal using the sample clock signal, and a Cascaded Integrator-Comb (CIC) filter circuit configured to generate the count value by performing cumulative amplification on the period counting value received from the periodic timer.

The operation detection circuit may be configured to generate a difference value by differentiating the count value received from the frequency digital converter, compare the difference value with a preset touch threshold value, and output a detection signal having a level based on a result of the comparing.

The touch detection circuit may include a delay device configured to receive the count value and delay the received count value by a period of time determined based on a delay control signal, and output a delay count value, a subtractor configured to generate a difference value by subtracting the count value from the delay count value; and a comparator configured to compare the difference value received from the subtractor with a preset touch threshold, and generate the detection signal which has a level that is based on a result of the comparison.

The comparator may be configured to generate a detection signal that has a level that indicates a touch occurrence when the difference value is equal to or less than the preset touch threshold.

The comparator may be configured to generate a detection signal that has a level that indicates a touch occurrence when the difference value rises to the preset touch threshold or higher after falling below the preset touch threshold.

In a general aspect, a method includes sensing, by a touch input pattern of a sensing device, a touch input, changing a capacitance of an oscillation circuit of the sensing device, generating an oscillation signal based on the change in capacitance, generating a detection signal by detecting the touch input based on a frequency included in the oscillation signal, and outputting a touch input detection signal.

The capacitance may be varied based on a touch occurrence that is sensed by the touch input pattern.

The method may further include converting the oscillation signal into a count value, and generating the detection signal based on the count value.

Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.

