WO2014190666A1

WO2014190666A1 - Detection circuit and detection method for power glitch signal

Info

Publication number: WO2014190666A1
Application number: PCT/CN2013/086267
Authority: WO
Inventors: 杨小坤; 原义栋; 赵东艳; 张海峰; 李振国
Original assignee: 国家电网公司; 北京南瑞智芯微电子科技有限公司
Priority date: 2013-05-31
Filing date: 2013-10-30
Publication date: 2014-12-04
Also published as: CN103675421A

Abstract

A detection circuit and detection method for a power glitch signal. The detection circuit comprises: a power supply, a comparator, a first capacitor, a second capacitor, a first resistor, a second resistor, and a third resistor, wherein the positive input port of the comparator is connected to one electrode of the power supply via the first capacitor, and the negative input port of the comparator is connected to the other electrode of the power supply via the second capacitor; the power supply comprises the positive electrode of the power supply and the negative electrode of the power supply; the first resistor, the second resistor and the third resistor are connected in series; a current is input from the first resistor, and the third resistor is connected to the ground; the first capacitor is connected to the positive input port of the comparator via a connection point of the first resistor and the second resistor; and the second capacitor is connected to the negative input port of the comparator via a connection point of the second resistor and the third resistor.

Description

Power supply glitch signal detecting circuit and detecting method

TECHNICAL FIELD The present invention relates to the field of embedded system technologies, and in particular, to a power glitch signal detecting circuit and a detecting method. BACKGROUND OF THE INVENTION A power glitch attack is to change a power supply voltage or a ground voltage input to a chip, causing certain circuit elements in the chip to be affected, causing one or more circuit units to enter an error state, thereby causing the chip processor. An attack that skips or implements erroneous operations based on the wrong state, thereby gradually revealing hidden security information within the chip. At this stage, with the wide application of smart cards, information cards in the field of information security have become the focus of attack by hackers.

In the prior art, the power glitch detection circuit generally includes four steps of glitch acquisition, calculation, comparison and latching. The comparison and latching are mainly realized by the comparator and the latch, and the acquisition and operation of the glitch are mainly realized by the resistor string. The purpose of detecting the glitch on the power supply is achieved by comparing the power supply voltage by a resistor string and comparing it with a fixed reference voltage. When the power supply voltage is glitched and its transient value is higher or lower than the reference voltage we set. The comparator generates an interrupt warning signal. In practical applications and chip designs, the voltage domain of the power glitch detection circuit is completely different from the voltage domain being attacked. While collecting the attacked voltage through the resistor string, it is necessary to consider whether the latter circuit can process the attack signal after the acquisition. In this case, it is inevitable to consider the actual signal input range of the latter circuit.

By considering the above prior art research and the actual circuit application environment, it is easy to find that the prior art has the following disadvantages:

(1) DC power consumption exists when the resistor string collects the power supply voltage.

(2) The resistor string can only collect the low frequency signal on the power supply, and the high frequency signal on the power supply cannot achieve the same ratio acquisition.

(3) When the detected DC voltage range of the power supply is large without glitch attacks, for example, when the battery voltage is supplied, the power supply voltage changes slowly from 5.5v to 2.7v, which increases the design difficulty of the subsequent comparison. SUMMARY OF THE INVENTION In order to solve the technical problem that the power glitch detecting circuit of the prior art has large power consumption and the detecting circuit itself is affected by the DC voltage variation of the detected power source, the present invention provides a power glitch signal detecting circuit and a detecting method.

According to an aspect of the invention, a power supply glitch signal detecting circuit includes: a power source, a comparator, a first capacitor, a second capacitor, a first resistor, a second resistor, and a third resistor,

The positive input port of the comparator is connected to one pole of the power source through a first capacitor, and the negative input port of the comparator is connected to the other pole of the power source through a second capacitor, the power source includes a positive pole of the power source and a negative pole of the power source; the first resistor, the second resistor, and The third resistor is connected in series; the current is input from the first resistor, and the third resistor is grounded; the first capacitor is connected to the positive input port of the comparator through a connection point of the first resistor and the second resistor; the second capacitor is passed through the second resistor and the third resistor The connection point of the resistor is connected to the negative input port of the comparator.

The detection circuit further includes a third capacitor, the first capacitor and the second capacitor being connected in series by the third capacitor.

When the positive input port of the comparator is connected to the positive terminal of the power supply through the first capacitor, the glitch signal voltage at the positive input port is: = , where is the glitch letter at the positive input port

Voltage; is the power supply glitch signal voltage; (^ is the capacitance value of the first capacitor, c ₃ is the capacitance value of the third capacitor.

When the positive input port of the comparator is connected to the negative supply of the power supply through the first capacitor, the glitch signal voltage at the positive input port is:

V _A = ^^Vcc , where is the glitch signal voltage at the positive input port; the power supply glitch signal voltage; (^ is the capacitance value of the first capacitor, and c ₃ is the capacitance value of the third capacitor.

The detection circuit also includes a shaper and a latch, and the comparator is coupled to the latch through a shaper.

In another aspect of the present invention, a power supply glitch signal detecting method includes: a first capacitor and a second capacitor collecting a glitch signal of a power source positive pole and a power source negative pole; the current sequentially passes through the first resistor, the second resistor, and the third resistor, A DC bias voltage provided for the comparator is generated at a connection point of the first resistor and the second resistor, and a connection point between the second resistor and the third resistor; the comparator obtains a glitch by comparing a voltage difference between the positive input port and the negative input port Signal voltage. The method further includes: the first capacitor, the second capacitor, and the third capacitor collecting a glitch signal of the positive pole of the power source and the negative pole of the power source.

The method further includes: the comparator further comparing the glitch signal voltage with an alarm threshold, and transmitting the comparison result to the shaper; the shaper converts the comparison result into a digital signal; the latch latches the digital signal, and when the comparison result is a glitch When the signal voltage is greater than the alarm threshold, the latch generates an interrupt warning signal.

The power supply glitch signal detecting circuit and the detecting method of the invention collect the glitch signal on the power source through the capacitor, and can isolate the DC voltage, so there is no DC power consumption; and, by isolating the DC voltage, the DC voltage value of the attacked power source occurs. The change does not affect the circuit of this proposal. The detection circuit is flexible and portable. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic structural view of an embodiment of a power supply glitch signal detecting circuit of the present invention;

2 is a schematic diagram of a power supply glitch signal of the present invention as a negative glitch signal;

3 is a schematic diagram of the power supply glitch signal of the present invention as a positive glitch signal;

4 is a schematic structural view of another embodiment of the power supply glitch signal detecting circuit of the present invention; FIG. 5 is a schematic structural view of another embodiment of the power glitch signal detecting circuit of the present invention; FIG. 6 is still another embodiment of the power glitch signal detecting circuit of the present invention; Schematic diagram of the structure. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings.

Embodiment 1

As shown in FIG. 1, the power supply glitch signal detecting circuit embodiment of the present invention includes: a power supply positive terminal VCC, a power supply negative electrode VSS, a comparator COMP, a first capacitor C1 and a second capacitor C2, a first resistor R1, and a second resistor R2. The third resistor R3.

The positive input port A of COMP is connected to VCC through C1, and the negative input port B of COMP is connected to VSS through C2.

Rl, R2 and R3 are connected in series. Current Ibias is input from R1 and R3 is grounded. C1 is connected to port A through the connection point of R1 and R2; C2 is connected to port B through the connection point of R2 and R3.

Current flows through the resistor string to produce voltages V _A and V _B at ports A, B, respectively. Voltages V _A and V _B are The latter comparator provides a DC bias. Due to the presence of the resistor R2, there is a certain voltage difference V _TH between the two points A and B, and the voltage difference V _TH is exactly the voltage amplitude of the power supply glitch signal to be detected.

When a glitch attack signal appears on the power supply voltage VCC, the capacitors C1 and C2 collect the glitch signal to the ports A and B, and isolate the DC signal of the power supply voltage from the ports A and B. Therefore, the VCC DC voltage conversion will not have any effect on the subsequent circuits.

The detection circuit in this embodiment further includes a shaper and a latch. The comparator is connected to the latch through a shaper.

The comparator further compares the glitch signal voltage to the alarm threshold and sends the comparison result to the shaper. The shaper converts the comparison result into a digital signal. The latch latches the digital signal. When the comparison result is that the glitch signal voltage is greater than the alarm threshold, the latch generates an interrupt warning signal. After that, the processor can perform real-time protection processing on each circuit unit according to the interrupt alarm signal to prevent information from being stolen.

Specifically, it is exemplified for FIG. 1. If the voltage output from VCC is used as the input signal, port A is used as the output terminal. If R ₂ + R ₃ »^, :^, and R ₃ are the resistance values of resistors R1, R2, and R3, respectively, then capacitor C1 and resistor R1 are formed. The high-pass filter circuit of the signal has a time constant of i;:!^*^, which is the capacitance value of the capacitor C1. Similarly, if +

Then R3 and C2 form a high-pass filter circuit whose time constant is T ₂ = R ₃ * C ₂ , and C ₂ is the capacitance value of the capacitor C2. When the frequency of the AC signal on the positive supply VCC and the negative supply VSS of the power supply is higher than the bandwidth of the high-pass filter A = r^- = _Ί = ~^T = J ^, the AC voltage components on the positive and negative poles of the power supply are respectively transmitted to Α, Two points. If the comparator is able to compare the maximum frequency of the input signal is f _t . _p , when the glitch circuit appears on VCC, then the frequency range of the VCC glitch signal that the detection circuit can detect is 3⁄4 ≤ fycc ≤ ^f top; Similarly, when the detection circuit appears on VSS, the detection circuit can detect The VSS glitch signal frequency range is f ₂ ≤ f _vss ≤ f _top .

In this embodiment,

=10ΜΩ, =C ₂ =lpf , at this time,

1

Fi = ^f 2 = 丽z. The highest frequency of the AC input signal that the comparator can detect is 1 GHz, and the frequency range of the glitch signal that the circuit can detect is << GHz. The DC voltage of the power supply VCC is 5.5V, and the voltage of VDD is 1.8V. If 1^=10]\^, Ibias = 0.1 A, the amplitude threshold of the glitch signal voltage that the detection circuit can detect is V _m = Ibias * R2 = lV .

In the actual application environment, as shown in Figure 2, the power glitch signal may be a negative glitch signal, which can be detected by using the detection circuit shown in Figure 1. As shown in Figure 3, the power glitch signal may also be a positive glitch attack signal, which can be detected using the detection circuit shown in Figure 4. The detection circuits of Figures 1 and 4 operate in the same way, except that the detected glitch signals are of opposite polarity. As shown in the detection circuit shown in Figure 4, the positive pole of the power supply is connected to the port B of the comparator through the capacitor C2, and the negative pole of the power supply is connected to the port A of the comparator through the capacitor C1.

The detecting circuit in this embodiment collects the glitch signal on the power source through the capacitor, and can isolate the DC voltage, so there is no DC power consumption; and, by isolating the DC voltage, the DC voltage value of the attacked power source changes. The circuit has no effect, and the detection circuit is flexible and portable.

In addition, the purpose of detecting positive and negative voltage glitch signals can be achieved by fine-tuning the circuit structure. Embodiment 2

In the actual circuit implementation process, the voltage of the glitch signal and the operating voltage of the detection circuit are issues that must be considered. When the operating voltage VDD of the detecting circuit is much smaller than the voltage amplitude of the glitch signal, the detecting circuit cannot normally detect the glitch signal.

In order to solve the above problem, as shown in FIG. 5 and FIG. 6, the power supply glitch signal detecting circuit of the present embodiment adds a third capacitor C3 based on the first embodiment. Cl and C2 are connected in series by C3. That is, the voltage of the glitch signal at the power source is divided by the capacitor C3 to lower the input port.

The glitch signal voltage at A. In Figure 5, the glitch signal voltage at the A port of the COMP is: V _A = ^Cl _cc , where is the glitch signal voltage at input port A; the glitch signal voltage at VCC; the capacitance value of capacitor C1, C ₃ is the capacitance value of the capacitor C3. In Figure 6, the glitch signal voltage at the A port of the COMP is: V _A = V .

The detection circuits in Figures 6 and 5 work in the same way, except that the detected glitch voltage signals are extremely opposite.

Specifically, it is exemplified with respect to Fig. 5.

If VCC is used as the input signal, port A is used as the output, if + Rz and R ₃ are the resistance values of the resistors R1, R2 and R3 respectively, then the capacitors Cl, C3 and the resistor R1 form a high-pass filter circuit for the signal, and the time constant is T:!^*^^^), and Cp C ₃ is the capacitor. The capacitance value of Cl and C3. Similarly, if + »^, then R3 and C2 form a high-pass filter circuit whose time constant is T ₂ = R ₃ * C ₂ , and C ₂ is the capacitance value of the capacitor C2. When the power supply positive VCC and the power supply negative VSS on the AC signal frequency is higher than the high-pass filter bandwidth

Fi = ! _τ = , „ l _(r ^ _Γλ ^ ^f 2 = _τ = ^ _Γ , the AC voltage components on the positive and negative poles of the power supply are respectively transmitted to points A and B. If the comparator can compare the maximum frequency of the input signal is f _t _p , when the glitch circuit appears on VCC, then the frequency range of the VCC glitch signal that the detection circuit can detect is A ≤ fyCC ≤ ^f top; Similarly, when the detection circuit appears on VSS, the detection circuit can detect The VSS glitch signal frequency range is f < f < f. In this embodiment, ^ = Κ ₃ = 1 Μ Ω, 3⁄4 = 10 Μ Ω, C _x = C ₂ = lpf , at this time, = ^ MHz , f ₂ = leg z. The maximum frequency of the AC input signal that the comparator can detect is 1 GHz. The frequency range of the VCC glitch signal that the circuit can detect is

-^MHz < f _vcc < IGHz - The frequency range of the VSS glitch that can be detected is 丄 ≤ f _vss < \GHz.

2π °

The DC voltage of the power supply VCC is 5.5V, and the voltage of VDD is 1.8V. If =10ΜΏ, 3⁄4ias = 0.1 zA, the amplitude threshold of the glitch signal voltage that the detection circuit can detect is V _m = 2 * Ibias * = 2V due to the voltage division of the AC signal by the capacitors CI and C3. It can be seen that the proper selection of the capacitor voltage ratio can make the detected glitch voltage threshold (2V) greater than the operating voltage of the circuit (1.8V).

In this embodiment, by adjusting the capacitance values of the capacitors C1 and C3, the voltage amplitude range of the glitch signal from the input port A can be conveniently adjusted, so that the detection circuit can normally detect the glitch signal with a large voltage amplitude.

The present invention further provides a power glitch signal detecting method, comprising: a first capacitor and a second capacitor collecting a glitch signal of a power source positive pole and a power source negative pole; the current sequentially passes through the first resistor, the second resistor, and the third resistor And generating a DC bias voltage for the comparator at a connection point of the first resistor and the second resistor, a connection point between the second resistor and the third resistor; comparing the voltage difference between the positive input port and the negative input port by the comparator Obtain the glitch signal voltage. Preferably, the method further includes: the first reference voltage and the second reference voltage provide a DC bias voltage to the comparator through the first resistor and the second resistor, respectively.

More preferably, the method further comprises: the comparator further comparing the glitch signal voltage with the alarm threshold, and transmitting the comparison result to the shaper; the shaper converts the comparison result into a digital signal; the latch latches the digital signal, when When the comparison result is that the glitch signal voltage is greater than the alarm threshold, the latch generates an interrupt warning signal.

It should be noted that the above embodiments are only intended to illustrate the present invention and are not intended to be limiting, and the present invention is not limited to the above examples, and all the technical solutions and improvements thereof without departing from the spirit and scope of the present invention should be covered by the present invention. In the scope of the claims.

Claims

Claim

What is claimed is: 1. A power supply glitch signal detecting circuit, comprising: a power supply, a comparator, a first capacitor, a second capacitor, a first resistor, a second resistor, and a third resistor,

The positive input port of the comparator is connected to one pole of the power source through a first capacitor, and the negative input port of the comparator is connected to the other pole of the power source through a second capacitor, where the power source includes a positive pole of the power source and a negative pole of the power source;

a first resistor, a second resistor, and a third resistor are connected in series; a current is input from the first resistor, and the third resistor is grounded;

The first capacitor is connected to the positive input port of the comparator through a connection point of the first resistor and the second resistor; the second capacitor is connected to the third resistor through the connection point of the second resistor The comparator's negative input port is connected.

2. The detection circuit according to claim 1, further comprising a third capacitor, wherein the first capacitor and the second capacitor are connected in series through the third capacitor.

3. The detecting circuit according to claim 2, wherein when the positive input port of the comparator is connected to the positive pole of the power source through the first capacitor, the glitch signal voltage at the positive input port is:

V _A = _cc V , where is the glitch signal voltage at the positive input port; the power supply glitch signal voltage; (^ is the capacitance value of the first capacitor, and c ₃ is the capacitance value of the third capacitor.

4. The detecting circuit according to claim 2, wherein when the positive input port of the comparator is connected to the negative pole of the power source through the first capacitor, the glitch signal voltage at the positive input port is:

V _A = ^^Vc _C , where is the glitch signal voltage at the positive input port; the power supply glitch signal voltage; (^ is the capacitance value of the first capacitor, and C ₃ is the capacitance value of the third capacitor.

The detection circuit according to any one of claims 1 to 4, further comprising a shaper and a latch.

The comparator is coupled to the latch by the shaper.

6. A power supply glitch signal detecting method, wherein a positive input port of a comparator is connected to a power source through a first capacitor, and a negative input port of the comparator is connected to another pole of the power source through a second capacitor. The power supply includes a positive pole of the power source and a negative pole of the power source; the first resistor and the second pole And a third resistor is connected in series; a current is input from the first resistor, and the third resistor is grounded; the first capacitor is connected to a positive input port of the comparator through a connection point between the first resistor and the second resistor Connecting; the second capacitor is connected to the negative input port of the comparator through a connection point of the second resistor and the third resistor; the method includes:

The first capacitor and the second capacitor collect the glitch signal of the positive pole of the power source and the negative pole of the power source; the current sequentially passes through the first resistor, the second resistor and the third resistor, at a connection point between the first resistor and the second resistor, the second resistor and the second resistor A DC bias voltage provided to the comparator is generated at the junction of the three resistors;

The comparator obtains the glitch signal voltage by comparing the voltage difference between the positive input port and the negative input port.

The detecting method according to claim 6, wherein the first capacitor and the second capacitor are connected in series through a third capacitor:

a first capacitor, a second capacitor, and a third capacitor collecting the power source positive pole and the power source negative pole glitch signal 8. The detecting method according to claim 7, wherein when the positive input port of the comparator passes the first capacitor When the positive pole of the power supply is connected, the glitch signal voltage at the positive input port is:

V _A = ^-^Vc _C , where is the glitch signal voltage at the positive input port; the power supply glitch signal voltage; (^ is the capacitance value of the first capacitor, and c ₃ is the capacitance value of the third capacitor.

The detecting method according to claim 7, wherein when the positive input port of the comparator is connected to the negative pole of the power source through the first capacitor, the glitch signal voltage at the positive input port is:

v _A = ^^v^ _c , where _A is the glitch signal voltage at the positive input port; is the power supply glitch signal voltage; (^ is the capacitance value of the first capacitor, and c ₃ is the capacitance value of the third capacitor.

The detection method according to any one of claims 6-9, wherein the comparator is connected to the latch through a shaper, the method further comprising:

The comparator further compares the glitch signal voltage with an alarm threshold, and sends a comparison result to the shaper;

The shaper converts the comparison result into a digital signal;

The latch latches the digital signal when the comparison result is the glitch letter The latch generates an interrupt warning signal when the voltage is greater than the alarm threshold.