ELECTRONIC CIRCUIT

• US 20120007438A1
• Filed: 08/04/2009
• Published: 01/12/2012
• Est. Priority Date: 08/26/2008
• Status: Active Grant

• Current Assignee: ThruChip Japan Inc.
• Original Assignee: KEIO University
• Inventors: Kuroda, Tadahiro
• Granted Patent: US 8,933,590 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/061 providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset removal of dc offset in coupling arrangements H04L25/029, H04L25/0296
• CPC Class Codes: H04L 25/40 Transmitting circuits; Receiving circuits repeater circuits, relay circuits H04L25/20
• CPC Class Codes: H04L 25/493 by transition coding, i.e. the time-position or direction of a transition being encoded before transmission

Abstract

A low-power high-speed asynchronous inductive-coupling transmission and reception technology is provided, in which a current signal of a single pulse is made to flow through a transmitting coil, and a voltage signal of a double pulse induced in an inductively-coupled receiving coil can be received asynchronously. A transmitting circuit for performing non-contact proximity communication adopts a configuration in which current flows through a first coil in a first direction for each change of a logical value of transmit data. A receiving circuit connected to a second coil coupled inductively to the first coil employs a comparator which determines an induced voltage of a double pulse induced in the second coil by current in the first direction and outputs a unipolar single pulse signal. Whenever the single pulse signal outputted by the comparator is inputted, the receiving circuit inverts the output in a sequential circuit and reproduces receive data.

Claims

1. An electronic circuit comprising:

a first substrate comprising a first coil and a transmitting circuit, the transmitting circuit making a pulse current in a first direction flow through the first coil at each change of logical values of transmit data with a prearranged logical value in the head; and

a second substrate comprising a second coil coupled inductively to the first coil and a receiving circuit connected to the second coil,

wherein the receiving circuit comprises;

a comparator outputting a single pulse signal with a single polarity, by determining, with the use of a threshold voltage, an induced voltage with a double pulse shape induced in the second coil by the pulse current in the first direction; and

a sequential circuit inverting the own output whenever the single pulse signal is inputted.

2. The electronic circuit according to claim 1,

wherein the comparator determines the induced voltage of the double pulse shape based on a threshold voltage of an input with a hysteresis characteristic, and whenever the logical value of the output signal is reversed, the threshold voltage changes.

3. The electronic circuit according to claim 2,

wherein the comparator comprises an initialization transistor switching the threshold voltage of the input to one of two values for initialization.

4. The electronic circuit according to claim 3,

wherein the initialization transistor performs the switching for initialization, before the head of the receive data is received.

5. The electronic circuit according to claim 3,

wherein the initialization transistor performs the switching for initialization for every separation of the receive data.

6. The electronic circuit according to claim 1,

wherein the first substrate further comprises a third coil and a third-coil transmitting circuit, the third-coil transmitting circuit making flow, through the third coil, a pulse current in a different direction depending on the change of a logical value of the transmit data with a prearranged logical value in the head,

wherein the second substrate further comprises a fourth coil coupled inductively to the third coil and a fourth-coil receiving circuit connected to the fourth coil,

wherein the third-coil transmitting circuit determines pulse width of the pulse current,

wherein the pulse width is made wide enough to shape an induced voltage induced in the fourth coil according to the rate of change of the pulse current, like a pair of single pulses with different polarities, and

wherein the fourth-coil receiving circuit comprises a hysteresis comparator determining the induced voltage with the shape of single pulses and outputting the determination result.

7. The electronic circuit according to claim 1,

wherein the first substrate further comprises a third coil and a third-coil transmitting circuit, the third-coil transmitting circuit making flow, through the third coil, a pulse current of a different direction depending on the change of a logical value of the transmit data,

wherein the second substrate further comprises a fourth coil coupled inductively to the third coil, a fourth-coil receiving circuit connected to the fourth coil, and a control circuit processing receive data received by the receiving circuit,

wherein the third-coil transmitting circuit determines the pulse width of the pulse current based on a delay time generated by a delay element,

wherein the pulse width is made wide enough to shape an induced voltage induced in the fourth coil according to the rate of change of the pulse current, like a pair of single pulses with different polarities,

wherein the fourth-coil receiving circuit comprises a hysteresis comparator determining the induced voltage with the shape of single pulses and outputting the determination result, wherein the transmit data comprises 2-bit dummy data with different logical values in the head, and

wherein the control circuit ignores two bits in the head of the receive data.