Integrated circuit device programming with partial power

• US 7,346,784 B1
• Filed: 08/29/2002
• Issued: 03/18/2008
• Est. Priority Date: 08/29/2002
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Theron, Conrad A.
• Primary Examiner(s): Perveen; Rehana
• Assistant Examiner(s): Stoynov; Stefan
• Application Number:
  US10/231,694
• Time in Patent Office: 2,028 Days
• Field of Search: 713/300
• US Class Current: 713/300
• CPC Class Codes: G01R 31/318516 Test of programmable logic devices [PLDs]
• CPC Class Codes: G11C 29/12005 comprising voltage or current generators
• CPC Class Codes: G11C 29/48 Arrangements in static stores specially adapted for testing by means external to the store, e.g. using direct memory access [DMA] or using auxiliary access paths
• CPC Class Codes: G11C 5/147 Voltage reference generators, voltage or current regulators; Internally lowered supply levels; Compensation for voltage drops G11C5/141 takes precedence
• CPC Class Codes: H03K 19/17736 Structural details of routing resources
• CPC Class Codes: H03K 19/17748 Structural details of configuration resources
• CPC Class Codes: H03K 19/17784 for supply voltage
• CPC Class Codes: H05K 1/029 having a programmable lay-out, i.e. adapted for choosing between a few possibilities
• CPC Class Codes: H05K 2201/10053 Switch
• CPC Class Codes: H05K 2201/10159 Memory
• CPC Class Codes: H05K 2201/10212 Programmable component
• CPC Class Codes: H05K 2201/10689 Leaded Integrated Circuit [IC] package, e.g. dual-in-line [DIL]

Abstract

A separate program power input is provided to a programmable logic array'"'"'s memory to permit it to be programmed independently of printed circuit board power. Means are provided to isolate the program power input from the array'"'"'s programmable logic circuit. Means are further provided to isolate the memory from the programmable logic circuit. The program power is not connected directly or indirectly to the programmable logic circuit thereby permitting the use of low-power devices to program the memory without connecting the printed circuit board to a power supply.

Claims

1. On a printed circuit board having a logic circuit, a memory circuit, and a printed circuit board power supply input connected to both the logic and memory circuits, the printed circuit board comprising:

a program power supply input coupled to the memory circuit;

means for electrically isolating the logic circuit from the memory circuit; and

means for electrically isolating the program power supply input from the logic circuit,

wherein the means for electrically isolating the program power supply input from the logic circuit comprises means selected from a group consisting of;

at least one normally open switch that closes in response to the presence of power on the printed circuit board power supply input;

a diode means connected between the program power supply input and the printed circuit board power supply input; and

a switch circuit powered in response to an absence of power on the printed circuit board power supply input.

2. The printed circuit board according to claim 1 further including programming controller logic coupled to the memory circuit, wherein the program power supply input is coupled to the programming controller logic.

3. The printed circuit board according to claim 2 wherein the programming controller logic comprises a JTAG controller.

4. The printed circuit board according to claim 1 wherein the memory circuit is selected from a group consisting of a flash memory and an electrically erasable memory.

5. The printed circuit board according to claim 1 wherein the logic circuit is selected from the group consisting of a field programmable gate array, a digital signal processor, a complex programmable logic device and a processor.

6. On a printed circuit board having a logic circuit, a memory circuit, and a printed circuit board power supply input connected to both the logic and memory circuits, the printed circuit board comprising:

a program power supply input coupled to the memory circuit;

means for electrically isolating the logic circuit from the memory circuit;

means for electrically isolating the program power supply input from the logic circuit; and

means for electrically isolating the logic circuit from circuitry external to the logic circuit and the memory circuit.

7. The printed circuit board according to claim 6 wherein the means for electrically isolating the logic circuit from the circuitry external to the logic circuit and the memory circuit comprises a normally open switch means that closes in response to presence of power on the circuit board power supply input.

8. On a printed circuit board having a logic circuit, a memory circuit, and a printed circuit board power supply input connected to both the logic and memory circuits, the printed circuit board comprising:

a program power supply input coupled to the memory circuit;

means for electrically isolating the logic circuit from the memory circuit;

means for electrically isolating the program power supply input from the logic circuit;

programming controller logic coupled to the memory circuit, wherein the program power supply input is coupled to the programming controller logic; and

power control means connected between the program power supply input and the memory circuit for changing voltage from the program power supply input in response to a command from the programming controller logic,

wherein the memory circuit has different voltages for writing to and reading from the memory circuit, the power control means adapted to change the program power supply input voltage to one of a reading voltage and a writing voltage in response to a control signal from the programming controller logic.

9. The printed circuit board according to claim 8 wherein the printed circuit board power supply input is connected through a diode.

10. The printed circuit board according to claim 8 wherein the printed circuit board power supply input is connected through a switch circuit powered in response to an absence of power on the printed circuit board power supply input.

11. A method for supplying programming power to a memory circuit of an integrated circuit while at the same time not supplying power to a logic circuit of the integrated circuit, comprising:

providing a program power supply input to the memory circuit;

providing a printed circuit board power supply input to both the memory circuit and the logic circuit;

providing means for electrically isolating the memory circuit from the logic circuit in response to power being present on the program power supply input but not on the printed circuit board power supply input; and

providing means for electrically isolating the program power supply input from the printed circuit board power supply input.

12. The method according to claim 11 further including the step of providing means for isolating the logic circuit from circuitry external to the integrated circuit in response to presence of power on the program power supply input and absence of power from the printed circuit board power supply input.

13. Integrated circuit means having separate memory and logic circuits, comprising:

means for providing printed circuit board power to both said memory and logic circuits; and

means for providing program power only to said memory circuit and for isolating said memory circuit from said logic circuit when said program power is present and said printed circuit board power is not present.

14. A programmable logic device, comprising:

programmable logic;

program memory selectively connected to the programmable logic;

a test control circuit coupled to the program memory, the test control circuit configured to instruct the program memory to load a program in response to a test mode select command;

a program-voltage input electrically decoupled from the programmable logic and coupled to the program memory; and

a power source coupled to the program memory via the program-voltage input, wherein the power source is electrically decoupled from the programmable logic.

15. The programmable logic device according to claim 14 further including a controller coupled between the program memory and the program-voltage input, and configured to select the power source voltage in response to instruction from the test control circuit.

16. The programmable logic device according to claim 15 wherein the power source is a battery.