DE102008049671A1 - Method for operating chip card controller, particularly radio frequency identification controller involves controlling leakage flow reduction device depending on field strength of power supply - Google Patents

Abstract

The method involves controlling leakage flow reduction device (2) depending on field strength (3) of power supply to chip card controller (1). The leakage flow reduction device is controlled by body biasing voltage (4) and virtual ground Voltage (5).

Description

The The present invention relates to a method of reduction of leakage currents, such as in smart card controllers can be used by means of energy provided.

A Reduction or minimization of leakage currents in integrated circuits Circuits is necessary to power consumption as low as possible to keep. This measure is under another increase in the temperature of the chip card controller minimized. Power consumption due to leakage currents can thereby reduced by being known in the literature Apply techniques such as body-biasing. It will raised a potential at the source terminal of a transistor, wherein the bulk voltage remains at a reference or ground potential remains. The power consumption due to leakage currents can significantly affect the overall power consumption of a system and thus, for example, the life of batteries in mobile Determine devices.

A further possibility for the reduction of leakage currents consists of a so-called "virtual ground" to use a virtual ground potential when the chip card controller in sleep mode, d. H. an access does not take place. Typically, integrated circuits are between a supply potential and a reference potential or ground potential connected. Is in for example, a sleep mode on the integrated circuit is not is accessed, becomes a fixed virtual ground potential used, which amounts in amount between the Massepotenti al and the supply potential. This results from the lower difference of potentials lower leakage currents the transistors of an integrated circuit and the data retention Time, the time in which the chip card controller works extended.

So far, the leakage current has been reduced only in dedicated operating modes of the smart card controller. The smart card controller can not react dynamically to changes in the power supply during an operating mode, for example, in "operation mode". Especially with RF-powered chip card controllers "energy gaps" can occur that in the standard ISO14443 type A are specified. In these "energy gaps", the electricity consumed, especially at high temperatures, especially the leakage current, must be supplied by the so-called support capacities.

Of the The present invention is therefore based on the object, a chip card controller whose energy consumption is adaptable in the operating modes is.

These Task is by the objects of the independent Claims 1 and 9 solved. The dependent ones Claims describe advantageous characteristics in each case of the present invention.

In a method according to the invention for operating a smart card controller with leakage current reduction device the leakage current reduction device is dependent a field strength for power supply of the chipcard controller controlled.

In A method for operating a smart card controller is the Leakage current reduction device by controlling a body biasing voltage controllable.

In A method for operating a smart card controller is the Leakage reduction device by controlling a virtual ground Voltage controllable.

In A method for operating a smart card controller is the Leakage current of the chip card controller by means of the leakage current reduction device before an expected change in field strength using Control of the supply voltage adjustable by hardware programs.

In A method for operating a smart card controller is the Leakage current of the chip card controller by means of the leakage current reduction device before an expected change in field strength using Control of the supply voltage adjustable by a software program.

In a method for operating a smart card controller is the data retention time is extended by reducing the leakage current. The Data Retention Time is a measure of the duration of the function a chip card controller.

In A method for operating a smart card controller is the Chip card controller an RFID controller.

In A method for operating a smart card controller is the Smart Card Controller is a contact based smart card controller.

One Smart card controller is suitable for use in the method to operate a smart card controller.

1 schematically shows a smart card controller with leakage current reduction device.

2 shows the extension of the data retention time as a function of the supply voltage.

3 shows the extension of the data retention time as a function of the body bias voltage and the virtual ground voltage.

The leakage current reduction device 2 of the 1 is suitable for controlling a reference voltage 4 . 5 and has a first entrance 6 for the supply voltage, a second input for a reference voltage Vref, a connection 7 for depending on the supply voltage 3 to be regulated reference voltage 4 . 5 and a connection 8th for a second reference voltage, or for a ground potential. The leakage current reduction device 2 So it's at her first entrance 6 with the supply voltage 3 connected, at its second input to the reference voltage, at its output 7 with the first reference voltage 4 . 5 and with the connection 8th is the leakage current reduction device 2 connected to the ground potential. The 1 schematically outlines a structure of a method for operating the leakage current reduction device, which the first reference voltage or the virtual ground potential 4 . 5 depending on the supply voltage 3 controls. The leakage current reduction device 2 for controlling the first reference voltage 4 . 5 controls the first reference voltage 4 . 5 so that always a data preservation in the smart card controller 1 can be guaranteed. At this point, it should be noted that the leakage current reduction device 2 can be realized in different ways. In general, the leakage current reduction device 2 a control circuit, which is the ertse reference voltage 4 . 5 depending on the (fluctuating) supply voltage controls. The reference voltage Vref at the input of the leakage current reduction device 2 can be realized for example by a so-called bandgag circuit. Simulations show that by means of in 1 shown leakage current reduction device 2 an extended functionality of the chip card controller 1 can be guaranteed.

2 shows a diagram in which the data retention time as a function of the supply voltage Vdd and the body bias voltage Vbs is shown. The Body Biasing voltage is Vbs 100 . 200 . 300 . 400 for different voltages (0 V, 0.2 V, 0.4 V and 0.6 V) entered in the diagram. The course of the body biasing voltage clearly shows that the data retention time increases due to the reduction of the body biasing voltage Vsb. 2 thus clearly shows that by means of Leckstromreducktionseinrichtung invention 2 the leakage current of the chip card controller 1 decreases and thus increases the data retention time.

3 shows a 3-D diagram in which the data retention time is plotted against the body bias voltage Vbs and the virtual ground voltage Vvg at high temperature. Also from the 3 It can be clearly seen that by means of the leakage current reduction device according to the invention 2 both with a suitable change of the body bias voltage Vbs, as well as with a suitable change of the virtual ground voltage Vvg the data retention time can be extended considerably. An extension of the data retention time, however, is synonymous with a reduction of the leakage current through the leakage current reduction device 2 ,

1

Smart card controller

2

Leakage current reduction device

3

Field strength Supply voltage Vdd

4

body Biasing voltage Vbs

5

Virtual Ground voltage Vvg

6

first entrance

7

second entrance

8th

Dimensions connection

100 200, 300, 400

course the body biasing tension

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - ISO14443 Type A [0004]

Claims (9)

Method for operating a chip card controller ( 1 ) with leakage current reduction device ( 2 ), in which method the leakage current reduction device ( 2 ) in dependence of a field strength ( 3 ) for the power supply of the chipcard controller ( 1 ) is controlled. Method according to claim 1, wherein the leakage current reduction device ( 2 ) by controlling a body biasing voltage ( 4 ) is controllable. Method according to claim 1, wherein the leakage current reduction device is controlled by means of a control of a virtual ground voltage ( 5 ) is controllable. Method according to one of the preceding claims, wherein a leakage current of the chip card controller ( 1 ) by means of the leakage current reduction device ( 2 ) before an expected change in field strength ( 3 ) is adjustable by means of hardware programs by controlling the supply voltage. Method according to one of the preceding claims, wherein a leakage current of the chip card controller ( 1 ) by means of the leakage current reduction device ( 2 ) before an expected change in field strength ( 3 ) is adjustable by controlling the supply voltage by a software program. Method according to one of the preceding claims, whereby the data retention time is reduced by reducing the leakage current is extended. Method according to one of the preceding claims, wherein the chip card controller ( 1 ) is an RFID controller. Method according to one of claims 1 to 6, wherein the chip card controller ( 1 ) a contact-based chip card controller ( 1 ). Chip card controller ( 1 ) for use in the process according to any one of the preceding claims.