Semiconductor device and wireless communication device

• US 8,928,374 B2
• Filed: 01/14/2014
• Issued: 01/06/2015
• Est. Priority Date: 03/05/2013
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Matsuno, Noriaki
• Primary Examiner(s): JAGER, RYAN C
• Application Number:
  US14/154,680
• Publication Number:
  US 20140253191A1
• Time in Patent Office: 357 Days
• Field of Search: 327/143, 365/226
• US Class Current: 327/143
• CPC Class Codes: H03K 17/22 Modifications for ensuring a predetermined initial state when the supply voltage has been applied bi-stable generators H03K3/12
• CPC Class Codes: H03K 17/223 in field-effect transistor switches
• CPC Class Codes: H03L 5/02 of power
• CPC Class Codes: H04B 1/40 Circuits

Abstract

To realize an optimal power-on reset in a system in which the rise of the power supply voltage is sharp.

A semiconductor device according to the present invention includes two diodes connected in parallel between power supplies, and a resistor circuit and a capacitance element connected in parallel between one power supply and each of the two diodes, and outputs a comparison result between voltages outputted from the two resistor circuits as a reset signal.

Claims

1. A semiconductor device comprising:

a first diode and a second diode that are connected in parallel in a forward direction between a first power supply and a second power supply;

a first resistor circuit and a first capacitor element that are connected in parallel between the first diode and the first power supply;

a second resistor circuit and a second capacitor element that are connected in parallel between the second diode and the first power supply; and

a comparator circuit that outputs a comparison result between a first voltage of a first node of the first resistor circuit and a second voltage of a second node of the second resistor circuit as a power-on reset signal,

wherein the first resistor circuit includes a first resistor element having one end coupled to the first power supply and the other end coupled to the first diode through the first node,

wherein the second resistor circuit includes a second resistor element and a third resistor element that are connected in series between the second diode and the first power supply through the second node, and

wherein a product of a resistance value between the second node and the second diode and a size of the first diode is smaller than a product of a resistance value between the first node and the first diode and a size of the second diode.

2. The semiconductor device according to claim 1,

wherein a capacitance ratio between the first capacitor element and the second capacitor element is substantially the same as a size ratio between the first diode and the second diode.

3. The semiconductor device according to claim 1,

wherein the first resistor circuit further includes a fourth resistor element having one end coupled to the first node and the other end coupled to the first diode, and

wherein a product of a resistance value of the third resistor element and a resistance value of the first resistor element is greater than a product of a resistance value of the fourth resistor element and a resistance value of the second resistor element.

4. The semiconductor device according to claim 1,

wherein the second resistor circuit includes a fifth resistor element connected in series between the third resistor element and the second diode.

5. The semiconductor device according to claim 1, further comprising:

at least one third diode connected in series in the forward direction between the first resistor element and the first power supply; and

at least one fourth diode connected in series in the forward direction between the second resistor element and the first power supply,

wherein the number of the third diodes and the number of the fourth diodes are the same.

6. The semiconductor device according to claim 1, further comprising:

at least one fifth diode coupled to the first diode in series in the forward direction; and

at least one sixth diode coupled to the second diode in series in the forward direction,

wherein the number of the fifth diodes and the number of the sixth diodes are the same.

7. The semiconductor device according to claim 1, further comprising:

a CR delay circuit that delays an output signal of the comparator circuit.

8. The semiconductor device according to claim 1, further comprising:

a plurality of switch circuits that controls coupling between an antenna and a plurality of ports; and

an I/F circuit which is coupled between the first power supply and the second power supply and which controls switching operations of the switch circuits on the basis of input data,

wherein the power-on reset signal is supplied to the I/F circuit, and

the I/F circuit is reset by the power-on reset signal of a first signal level and the reset of the I/F circuit is released by the power-on reset signal of a second signal level.

9. A wireless communication device comprising:

the semiconductor device according to claim 8; and

a plurality of transmitter circuits and a plurality of receiver circuits, which are coupled to the ports.