Touch/key sensing with N-1 key scan averaging, for use with an N-key touch input apparatus, including a key matrix of N touch-key sense circuits, including: (a) continuously scanning the key matrix at a first bandwidth to determine a respective touch-key baseline sense signal, independent of a key-press condition, and a related touch-key baseline value based on successive baseline sense signals; and (b) during successive key-scan periods, scanning the key matrix at a second bandwidth greater than the first bandwidth, and for each touch key N, determining a touch-key sense signal, generating an N-1 key-scan average value by averaging the touch-key baseline values for the other N-1 touch keys, comparing the Nth touch-key sense signal to a key-press threshold based on the N-1 key-scan average value; and (c) signaling a key-press condition if the touch-key sense signal is greater in magnitude than the N-1 key-scan average value by the key-press threshold.

Touch/key sensing with N-1 key scan averaging, for use with an N-key touch input apparatus, including a key matrix of N touch-key sense circuits, including: (a) continuously scanning the key matrix at a first bandwidth to determine a respective touch-key baseline sense signal, independent of a key-press condition, and a related touch-key baseline value based on successive baseline sense signals; and (b) during successive key-scan periods, scanning the key matrix at a second bandwidth greater than the first bandwidth, and for each touch key N, determining a touch-key sense signal, generating an N-1 key-scan average value by averaging the touch-key baseline values for the other N-1 touch keys, comparing the Nth touch-key sense signal to a key-press threshold based on the N-1 key-scan average value; and (c) signaling a key-press condition if the touch-key sense signal is greater in magnitude than the N-1 key-scan average value by the key-press threshold.

A keyboard device that is applicable to various kinds of applications with high responsivity is provided.

The keyboard device includes a group of keys 10 composed of a plurality of keys to which key addresses are assigned; a memory 13 in which, for each of the plurality of keys, threshold data for determining whether the key has been depressed is writable and readable in a memory address corresponding to a corresponding one of the key addresses; a key capacitance detecting unit 15 that detects a capacitance of the key corresponding to the key address that is selected; a capacitance-voltage converting unit that converts the capacitance of the key detected by the key capacitance detecting unit into a voltage; a data converting unit 16 that reads threshold data in the memory address in the memory corresponding to the key address that is selected to convert the threshold data into analog data; and a depression determining unit 18 that compares the analog data from the data converting unit with the voltage from the capacitance-voltage converting unit to determine whether the key has been depressed.

A keyboard system includes a keyboard matrix; and an embedded controller in communication with the keyboard matrix, wherein the embedded controller is configured to: determine whether, in a single scan cycle of the keyboard matrix, multiple keys have been pressed or only a single key has been pressed; if only a single key has been pressed, learn an order of pressed keys in a plurality of scan cycles; and if multiple keys have been pressed, generate an order of the pressed multiple keys based on the learned order of pressed keys.

A keyboard apparatus including a key module and a detection circuit is provided. The key module includes a plurality of keys, a plurality of scan lines and a plurality of return lines. The scan lines and the return lines are crossed to each other and respectively coupled to the keys. The detection circuit detects a plurality of return voltages of the return lines and generates a plurality of detection signals accordingly so as to indicate that a switch of each of the keys is at an on state or at an off state. The detection circuit includes a plurality of P-type transistors. A first terminal of each P-type transistor is coupled to a ground terminal, a control terminal of each P-type transistor is directly coupled to a corresponding one of the return lines, and a second terminal of each P-type transistor generates and outputs one of the detection signals.

A keyboard apparatus including a key module and a detection circuit is provided. The key module includes a plurality of keys, a plurality of scan lines and a plurality of return lines. The scan lines and the return lines are crossed to each other and respectively coupled to the keys. The detection circuit detects a plurality of return voltages of the return lines and generates a plurality of detection signals accordingly so as to indicate that a switch of each of the keys is at an on state or at an off state. The detection circuit includes a plurality of P-type transistors. A first terminal of each P-type transistor is coupled to a ground terminal, a control terminal of each P-type transistor is directly coupled to a corresponding one of the return lines, and a second terminal of each P-type transistor generates and outputs one of the detection signals.

A keyboard system includes a keyboard matrix; and an embedded controller in communication with the keyboard matrix, wherein the embedded controller is configured to: determine whether, in a single scan cycle of the keyboard matrix, multiple keys have been pressed or only a single key has been pressed; if only a single key has been pressed, learn an order of pressed keys in a plurality of scan cycles; and if multiple keys have been pressed, generate an order of the pressed multiple keys based on the learned order of pressed keys.

A keyboard scanning circuit includes a plurality of switching elements, M scanning lines and N sensing lines. Each of the sensing lines has a common node extended to M transmission lines. A switching element is coupled where one of the transmission lines and one of the scanning lines intersects. Two scanning lines correspondingly coupled through two switching elements to two transmission lines extended from one sensing line are different from each other.

A keyboard scanning circuit includes a plurality of switching elements, M scanning lines and N sensing lines. Each of the sensing lines has a common node extended to M transmission lines. A switching element is coupled where one of the transmission lines and one of the scanning lines intersects. Two scanning lines correspondingly coupled through two switching elements to two transmission lines extended from one sensing line are different from each other.

A keyboard device includes M driving circuits DC(1)DC(M), N transition circuits TC(1)TC(N), a control module, M column signal lines C(1)C(M), N row signal lines R(1)R(N) and M*N key units KU(1,1)KU(M,N). The control module performs a scanning process to sequentially scan the M column signal lines C(1)C(M) in M scan cycles scan(1)scan(M). If the key unit KU(k,x) connected with the k-th column signal line C(k) and the x-th row signal line R(x) is depressed, a scan voltage is transmitted from the k-th column signal line C(k) to the x-th row signal line R(x) through a switch sw(k,x) of the key unit KU(k,x). The transition circuit TC(x) connected with the x-th row signal line R(x) is turned on according to the scan voltage. Consequently, an output voltage Rout(x) from the transition circuit TC(x) has a first voltage level.