A new power architecture for large-capacity SIM card chips

Abstract

The present invention provides a new power supply architecture suitable for a large-capacity SIM card chip, including a bandgap reference circuit, a voltage detection circuit, a current source, a current bypass circuit, a frequency alarm circuit, a burr filtering capacitor and a low-voltage difference linear regulator; wherein the bandgap reference circuit is connected to the voltage detection circuit, the voltage detection circuit is connected to the current source and the current bypass circuit, the current source is connected to the current bypass circuit, the frequency alarm circuit is respectively connected to the current source, the current bypass circuit and the burr filtering capacitor, and the burr filtering capacitor is connected to the low-voltage difference linear regulator and an external large-capacity SIM card chip. The present invention designs a new overcurrent alarm scheme, which effectively filters out most of the power consumption glitches when the digital circuit is running while ensuring that the circuit power consumption does not exceed the standard, thereby reducing the number of alarms; effectively shielding the power consumption fluctuation of the chip at the power supply VCC port, preventing the DPA attack from the power supply VCC port, and improving the security of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits of SIM cards, and in particular to a new power supply architecture suitable for large-capacity SIM card chips. Background Art

[0002] Voltage level Current Class A (4.5~5.5V) <10mA Class B (2.7~3.3V) <h2 style=";text-align:left;direction:ltr"><6mA<h2 style=";text-align:left;direction:ltr"> Class C (1.62~1.78V) <4mA

[0003] In the design of the new generation of SIM card chips, it is necessary to increase the chip's operating speed as much as possible under rated current. In addition to process improvements, the improvement of SIM card chip operating speed also requires optimization of analog power system design to increase the system operating frequency as much as possible under limited current conditions.

[0004] In the security technology of large-capacity SIM card chips, preventing DPA (Differential Power Analysis) attacks is a key technology. DPA attacks use the changes in power consumption when the chip executes different instruction operations to analyze the cryptographic algorithm and restore the secret key, thereby achieving the effect of the attack. In digital circuit design, the security capabilities of the chip are usually improved by adding redundant power consumption. However, with the improvement of security attack technology, it is not enough to simply add digital redundant power consumption. It is also necessary to completely shield the changes in digital power consumption in the analog power supply design to prevent the leakage of chip power consumption fluctuations.

[0005] See also Figure 1 As shown in the figure, it is a block diagram of the existing SIM card chip power system, which is mainly composed of a bandgap reference circuit (Bandgap Reference, BRG), a voltage detection circuit (Voltage Detector, VD), a low drop out regulator (Low Drop Out Regulator, LDO), and an over current protection circuit (Over Current Protection, OCP) circuit.

[0006] The bandgap reference circuit BRG generates a reference voltage VREF and a reference current IREF, and provides a reference voltage Vref and a reference current Iref for the voltage detection circuit VD, the low-dropout linear regulator LDO and the overcurrent protection circuit OCP; the voltage detection circuit VD detects the size of the power supply VCC, determines the Class ABC voltage level of the power supply VCC, outputs a voltage detection signal VD<1:0>, and sets the current threshold of the overcurrent protection circuit OCP; the low-dropout linear regulator LDO provides the core voltage VDD, and the low-dropout linear regulator OCP detects the size of the power tube current flowing through the low-dropout linear regulator LDO, and provides an overcurrent alarm signal V for the digital circuit. ocp ;I VCC is the total current consumed by the chip, I loadis the current consumed by the digital circuit. Since the power consumption of the analog circuit is much smaller than that of the digital circuit, I VCC Approximately equal to I load , which is the current flowing through the power tube in the low dropout linear regulator LDO.

[0007] When the SIM card chip is actually working, the voltage detection circuit VD detects and determines the power supply VCC level, and sets the threshold current size for the low-dropout linear regulator OCP according to the Class ABC voltage level of the power supply VCC; the overcurrent protection circuit OCP detects I load (I VCC ) current, once it exceeds the current threshold of the corresponding Class ABC voltage level, the output V ocp Set the alarm high to reduce the chip's operating frequency, thereby reducing I load To meet the rated current requirements under the corresponding power supply VCC level.

[0008] Figure 2 The circuit structure diagram of the existing low voltage drop linear regulator is shown in Figure 1. The power tube is connected in series between the external power supply VCC and the internal core voltage VDD. The power consumption of the digital circuit can be directly monitored through the power supply VCC, which brings security risks to the chip.

[0009] Figure 3 As shown in FIG. 1 , it is a schematic diagram of the power consumption of the existing SIM card chip system. Figure 3 As shown, they are system power consumption I load , Overcurrent protection circuit OCP alarm voltage V ocp As well as the diagram of the system operating frequency changing over time, it can be seen that once I load Exceeding the threshold I th , V ocp Set high alarm, the system frequency changes from high frequency f H Down to low frequency f L , and maintain for a period of time t hold , ensuring that the system meets the current requirements in the protocol.

[0010] The problems existing in the existing SIM card chip power architecture are as follows:

[0011] 1) It is impossible to shield the power consumption of the digital circuit in the SIM card chip. In the existing low-dropout linear regulator LDO circuit structure, the power tube is connected in series between the external power supply VCC and the internal core voltage VDD. The power consumption of the digital circuit of the SIM card chip can be directly monitored through the power supply VCC, which brings security risks to the SIM card chip;

[0012] 2) When the SIM card chip system runs with high power consumption and many power consumption glitches, the low-dropout linear regulator LDO needs to respond quickly to maintain the stability of the core voltage VDD, that is, the current in the low-dropout linear regulator LDO power tube will change dramatically, and it is easy to exceed the rated current value, generate alarm consumption, and reduce the system operation speed;

[0013] 3) Therefore, if the digital power consumption glitches of the SIM card chip system cannot be filtered out, the low-dropout linear regulator OCP will frequently alarm, causing the system to operate at a low frequency f for a long time. L Running, greatly reducing the overall system speed. Summary of the invention

[0014] In view of the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a new power supply architecture suitable for a large-capacity SIM card chip, including a bandgap reference circuit, a voltage detection circuit, a current source, a current bypass circuit, a frequency alarm circuit, a glitch filtering capacitor and a low-dropout linear regulator. A new overcurrent alarm system is designed to effectively filter out most of the power consumption glitches when the digital circuit is running while ensuring that the circuit power consumption does not exceed the standard, thereby reducing the number of alarms and improving the safety of the system.

[0015] In order to achieve the above technical purpose, the technical solution adopted by the present invention is:

[0016] A new power supply architecture suitable for a large-capacity SIM card chip, the new power supply architecture comprising a bandgap reference circuit, a voltage detection circuit, a current source, a current bypass circuit, a frequency alarm circuit, a glitch filtering capacitor and a low-voltage dropout linear regulator; wherein the bandgap reference circuit is connected to the voltage detection circuit, the voltage detection circuit is connected to the current source and the current bypass circuit, the current source is connected to the current bypass circuit, the frequency alarm circuit is respectively connected to the current source, the current bypass circuit and the glitch filtering capacitor, and the glitch filtering capacitor is connected to the low-voltage dropout linear regulator and an external large-capacity SIM card chip;

[0017] The bandgap reference circuit generates a reference voltage and a reference current, and is connected to a voltage detection circuit, a current source, a current bypass circuit, a frequency alarm circuit and a low-dropout linear regulator;

[0018] The voltage detection circuit detects the voltage level of the power supply and outputs a voltage detection signal connected to the current source to control the output current of the current source to meet the requirements of the 7816 protocol; the output current of the current source is connected to the current bypass circuit, the frequency alarm circuit, the burr filtering capacitor and the low voltage drop linear regulator;

[0019] The frequency alarm circuit is connected to the output end of the current source, detects the input power supply, generates an alarm signal, and controls the operating frequency of the digital circuit in the SIM card chip;

[0020] A low voltage drop linear regulator provides a core voltage for a digital circuit in the SIM card chip;

[0021] The burr filtering capacitor filters out high power consumption burrs when the digital circuit in the SIM card chip is running.

[0022] The novel power supply architecture applicable to a large-capacity SIM card chip of the present invention adopts the structure of the bandgap reference circuit BGR, the voltage detection circuit VD, the current source CS, the current bypass circuit CB, the frequency alarm circuit FA, the burr filtering capacitor C1 and the low voltage difference linear regulator LDO, and the beneficial effects obtained are:

[0023] 1) A current source controlled by a voltage detection circuit VD is designed to automatically set the system rated current according to the power supply VCC voltage level. While meeting the 7816 protocol, the current change at the power supply VCC PIN input terminal is completely shielded;

[0024] 2) The traditional over-current protection circuit OCP over-current alarm circuit was removed, and a new over-current alarm scheme was designed. While ensuring that the circuit power consumption does not exceed the standard, most of the power consumption glitches during the operation of the digital circuit are effectively filtered out, reducing the number of alarms;

[0025] 3) Effectively shield the power consumption fluctuation of the chip at the power VCC port, prevent DPA attacks from the power VCC port, and improve the security of the system;

[0026] 4) The new overcurrent alarm scheme can filter out power consumption glitches during the operation of digital circuits, greatly improving the system's operating speed while meeting the protocol. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 It is a block diagram of the existing SIM card chip power supply system.

[0029] Figure 2 It is a circuit structure diagram of an existing low voltage dropout linear regulator.

[0030] Figure 3 This is a schematic diagram of the power consumption operation of an existing SIM card chip system.

[0031] Figure 4 This is a block diagram of a new power supply architecture suitable for a large-capacity SIM card chip of the present invention.

[0032] Figure 5 is the load power consumption I of the SIM card chip system during operation of the present invention. load , power supply voltage VCC1, alarm voltage V fa and a graph of system frequency versus time.

[0033] Figure 6 This is a new power supply architecture diagram applicable to a large-capacity SIM card chip implemented in the present invention.

[0034] Figure 7 It is a structural diagram of a voltage detection circuit specifically implemented in the present invention. DETAILED DESCRIPTION

[0035] See also Figure 4 The figure shows a block diagram of a new power supply architecture suitable for a large-capacity SIM card chip of the present invention. The new power supply architecture suitable for a large-capacity SIM card chip includes a bandgap reference circuit BGR, a voltage detection circuit VD, a current source CS, a current bypass circuit CB, a frequency alarm circuit FA, a glitch filtering capacitor C1 and a low-voltage dropout linear regulator LDO; the bandgap reference circuit BGR is connected to the voltage detection circuit VD, the voltage detection circuit VD is connected to the current source CS and the current bypass circuit CB, the current source CS is connected to the current bypass circuit CB, the frequency alarm circuit FA is connected to the current source CS, the current bypass circuit CB and the glitch filtering capacitor C1 respectively, the glitch filtering capacitor C1 is connected to the low-voltage dropout linear regulator LDO and the external large-capacity SIM card chip ASIC; the bandgap reference circuit BGR generates a reference voltage and a reference current, which are connected to the voltage detection circuit VD, the current source CS, the current bypass circuit CB, the frequency alarm circuit FA, the glitch filtering capacitor C1 and the low-voltage dropout linear regulator LDO. Bypass circuit CB, frequency alarm circuit FA and low voltage difference linear regulator LDO; voltage detection circuit VD detects the voltage level of power supply VCC and outputs voltage detection signal VD<1:0> connected to current source CS to control the output current of current source CS to meet the requirements of 7816 protocol; the output current of current source CS is connected to current bypass circuit CB, frequency alarm circuit FA, burr filtering capacitor C1 and low voltage difference linear regulator LDO; frequency alarm circuit FA is connected to the output end of current source CS to detect input power supply VEE and generate alarm signal Vfa to control the operating frequency of digital circuit in the SIM card chip; low voltage difference linear regulator LDO provides core voltage VDD for digital circuit in the SIM card chip; burr filtering capacitor C1 filters out high power consumption burrs when the digital circuit in the SIM card chip is running.

[0036] See also Figure 4As shown, in the 7816 protocol, the entire operating voltage range of the SIM card chip is specified to be 1.62V~5.5V, among which the minimum voltage of the power supply VCC is 1.62V. In order to ensure that the current source CS has a voltage space of 220mV and can output the accurate rated current, VCC1 is designed to be 1.4V, and the core voltage VDD is 1.2V; in order to ensure that the low-dropout linear regulator LDO can normally output a voltage of 1.2V, a voltage difference of 100mV is required, and the alarm voltage of the frequency alarm circuit FA is designed to be 1.3V.

[0037] See also Figure 4 As shown in the figure, taking the Class A scenario with power supply voltage VCC=5V as an example, after the SIM card chip is powered on, the voltage detection circuit VD detects that VCC=5V, outputs the control signal VD<1:0>=0b11, and inputs it to the current source CS to control the current source CS to generate an output current Iout=10mA. In this way, the entire SIM card chip is limited to 10mA throughout the entire working cycle. While meeting the 7816 protocol, it effectively shields the fluctuation of digital power consumption and prevents DPA attacks at the power supply VCC port.

[0038] There are three situations when the digital circuit of the SIM card chip is running:

[0039] 1) When the low dropout linear regulator LDO load I load <10mA, the current bypass circuit CB passes the bypass current I bypass Maintain the current source CS output voltage VCC1 = 1.4V;

[0040] 2) When the low dropout linear regulator LDO load I load >10mA, but when the burr is small, the charge stored in the burr filtering capacitor C1 can provide the low voltage drop linear regulator LDO for zero time, maintain the power supply voltage VCC1>1.3V, do not trigger the frequency alarm circuit FA alarm, and maintain the high-speed operation of the SIM card chip. The size of the burr that the SIM card chip system can filter depends on the size of the burr filtering capacitor C1; considering the area of ​​the SIM card chip and the types of most burrs, the burr filtering capacitor C1 is usually designed to be around 500pF;

[0041] 3) When the low dropout linear regulator LDO load power consumption I load >10mA, and the glitch is large, the charge in the glitch filtering capacitor C1 cannot maintain the power supply voltage VCC1 above 1.3V, the frequency alarm circuit FA alarms, the SIM card chip system reduces the frequency, and the low voltage drop linear regulator LDO load power consumption I load The power supply voltage VCC1 drops and returns to 1.4V, ensuring the safety of the operating voltage of the SIM card chip system.

[0042] See also Figure 5 As shown, the load power consumption I of the SIM card chip system during operation of the present invention is shown. load , power supply voltage VCC1, alarm voltage V fa And the system frequency changes over time. Figure 3 By comparison, it is found that under the new power architecture suitable for large-capacity SIM card chips, most of the digital power consumption glitches can be filtered out by the glitches filtering capacitor C1, and no alarm is generated. The SIM card chip system operates at a high frequency f H Only in a few cases of large glitches will the alarm voltage V be triggered. fa Set high alarm and run at low frequency f L Therefore, the new power supply architecture effectively filters out most of the power consumption glitches and greatly improves the system operation speed.

[0043] See also Figure 6 FIG. 1 is a diagram of a new power supply architecture for a large-capacity SIM card chip according to a specific implementation of the present invention. Figure 7 As shown in FIG. 1 , it is a structure diagram of a voltage detection circuit specifically implemented in the present invention. Figure 7 As shown, the voltage of the power supply VCC is sampled by a resistor and compared with the reference voltage Vref. The first resistor RS1 is designed to be 200Kohm; the second resistor RS2 is designed to be 40Kohm; the third resistor RS3 is designed to be 60Kohm, and the reference voltage Vref is designed to be 0.8V.

[0044] VC1 VC2 Voltage level 0 0 Class C 0 1 Class B 1 0 -- 1 1 Class A

[0045] Input voltage level Input VCC Range Output VD<2:0> Class A 4.5V~5.5V 100 Class B 2.7V~3.3V 010 Class C 1.62V~1.78V 001

[0046] CEO<2:0> IB 100 50uA 010 30uA 001 20uA

[0047] Combination Figure 6 As shown, the current source CS is composed of a reference current source IB, a first power tube MP1, a second power tube MP2, a third power tube MP3 and a first error amplifier EA1. The reference current source IB controls the output current I out The first power tube MP1, the second power tube MP2, the third power tube MP3 and the first error amplifier EA1 form a precise current mirror; the error amplifier ensures that the drain voltage of the first power tube MP1 is equal to the drain voltage of the second power tube MP2, reducing the mirror error. The mirror ratio of the first power tube MP1 and the second power tube MP2 is 1:200, and the reference current source IB is amplified 200 times.

[0048] Combination Figure 6As shown, it can be calculated that the voltage detection circuit VD and the current source CS circuit can make the SIM card chip input current from the power supply VCC port to be 10mA, 6mA and 4mA respectively under Class ABC conditions, which is not affected by the load power consumption. While meeting the 7816 protocol, it completely shields the load power consumption fluctuation, greatly improving the security of the SIM card chip.

[0049] Combination Figure 6 As shown, the current bypass circuit CB is a negative feedback system composed of a first resistor R1, a second resistor R2, a second error amplifier EA2 and a fourth power tube MP4. The first resistor R1 and the second resistor R2 sample the power supply voltage VCC1 to output a sampled voltage Vsample. When the sampled voltage Vsample is greater than the reference voltage Vref, the output of the second error amplifier EA2 decreases, and the bypass current I bypass increases, the power supply voltage VCC1 decreases; when the sampling voltage Vsample is less than the reference voltage Vref, the output of the second error amplifier EA2 increases, and the bypass current I bypass The power supply voltage VCC1 decreases, and the power supply voltage VCC1 increases. Finally, the power supply voltage VCC1=Vref*((R1+R2) / R2) is controlled. The reference voltage Vref=0.8V is designed, the first resistor R1=600Kohm, and the second resistor R2=800Kohm. The power supply voltage VCC1=1.4V is calculated. bypass When the power supply voltage VCC1 is exhausted, that is, when Ibypass=0, the power supply voltage VCC1 is still less than 1.4V, the loop of the current bypass circuit CB fails and the power supply voltage VCC1 continues to drop.

[0050] The frequency alarm circuit FA adopts a structure similar to that of the voltage detection circuit VD. The alarm threshold is designed to be 1.3V. When the power supply voltage VCC1>1.3V, V fa = "1", the digital circuit of the SIM card chip is controlled to run at a low frequency f L Otherwise, the digital circuit of the SIM card chip runs at high frequency f H .

[0051] Combination Figure 6 As shown, the capacitance of the burr filtering capacitor C1 is designed to be 500pF; the low-dropout linear regulator LDO adopts a traditional negative feedback structure, consisting of a third resistor R3, a fourth resistor R4, a third error amplifier EA3 and a fifth power tube MP5, the core voltage VDD=Vref*((R3+R4) / R4), the reference voltage Vref=0.8V, the fourth resistor R4=400Kohm, the third resistor R3=200Kohm, and the core voltage VDD=1.2V can be obtained by calculation.

[0052] When the SIM card chip ASIC works, it can be divided into the following three situations:

[0053] 1) When the low dropout linear regulator LDO load power consumption I load The output current I of the reference current source IB is smaller. out Larger, that is, I load out When the current bypass circuit CB loop starts, I out =I load +I bypass , the power supply voltage VCC1 is limited to 1.4V by the current bypass circuit CB loop, the frequency alarm circuit FA will not trigger an alarm, Vfa = "0", and the SIM card chip system runs at a high frequency f H ;

[0054] 2) When the low dropout linear regulator LDO load power consumption I load When the burr is small, I load Greater than I out , the current bypass circuit CB loop fails, and the fourth power tube MP4 bypass current I bypass =0, the power supply voltage VCC1 decreases, I load The current is supplemented by the glitch filtering capacitor C1, but before the power supply voltage VCC1 drops to the 1.3V alarm threshold, I load Back to I out Next, the current bypass circuit CB loop restarts and the power supply voltage VCC1 recovers to 1.4V. In this case, although I load Short-term greater than I out , but the frequency alarm circuit FA did not alarm, and the SIM card chip system has been running at high frequency f H , the power consumption glitches are “filtered out”;

[0055] 3) When the low dropout linear regulator LDO load power consumption I load When the burr is large, I load Continue to be greater than I out , the current bypass circuit CB loop fails, and the fourth power tube MP4 bypass current I bypass =0, the power supply voltage VCC1 decreases, I load The current is supplemented by the glitch filtering capacitor C1 until the power supply voltage VCC1 drops to 1.3V, triggering the frequency alarm circuit FA to alarm, V fa Set high to control the SIM card chip system to reduce the frequency to f L , I load Down to I out ​Next, the current bypass circuit CB loop is started, and the power supply voltage VCC1 is restored to 1.4V. During the entire process, the power supply voltage VCC1>1.3V, ensuring that the core voltage VDD stably outputs 1.2V.

[0056] From the above, it can be concluded that the SIM card chip using the new power supply architecture not only meets the 7816 protocol, but also effectively shields the power consumption of the digital circuit in the SIM card chip, thereby improving the safety performance of the SIM card chip system; and the new power supply architecture innovatively designs a new alarm system, which filters out most of the power consumption glitches during the operation of the SIM card chip system, greatly improving the operating speed of the system; and, under the same process conditions, simulation shows that it can be concluded that the operating speed of the SIM card chip using the new power supply architecture is effectively increased by more than 1.5 times.

[0057] It should be noted that the above embodiments are only schematic illustrations of the basic concept of the present invention, and the component circuits related to the present invention are not drawn according to the number, shape, device arrangement, and connection method of the component circuits in actual implementation. The type, number, connection method, device arrangement, and device parameters of each circuit in actual implementation can be changed at will.

[0058] The above-described embodiments are only preferred embodiments of the present invention and cannot limit the extension of the technical solution of the present invention. Any modification, equivalent change and obvious replacement of the known technology made by those skilled in the art on the basis of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A new power supply architecture suitable for large-capacity SIM card chips, characterized in that: The novel power supply architecture includes a bandgap reference circuit, a voltage detection circuit, a current source, a current bypass circuit, a frequency alarm circuit, a glitch filtering capacitor and a low voltage drop linear regulator; wherein, The bandgap reference circuit is connected to the voltage detection circuit, the voltage detection circuit is connected to the current source and the current bypass circuit, the current source is connected to the current bypass circuit, the frequency alarm circuit is respectively connected to the current source, the current bypass circuit and the burr filtering capacitor, and the burr filtering capacitor is connected to the low voltage difference linear regulator and the external large-capacity SIM card chip; The bandgap reference circuit generates a reference voltage and a reference current, which are connected to a voltage detection circuit, a current source, a current bypass circuit, a frequency alarm circuit and a low-dropout linear regulator; the voltage detection circuit detects the voltage level of the power supply, and outputs a voltage detection signal connected to the current source to control the output current of the current source to meet the requirements of the 7816 protocol; the output current of the current source is connected to a current bypass circuit, a frequency alarm circuit, a glitch filtering capacitor and a low-dropout linear regulator; The frequency alarm circuit is connected to the output end of the current source to detect the input power supply; A low voltage drop linear regulator provides a core voltage for a digital circuit in the SIM card chip; The burr filtering capacitor filters out the high power consumption burrs when the digital circuit in the SIM card chip is running; When the load of the low-dropout linear regulator is large but the burr is small, the frequency alarm circuit is not triggered to alarm, and the digital circuit in the SIM card chip is maintained to operate at a high frequency; When the load power consumption of the low voltage difference linear regulator is large and the burr is large, the frequency alarm circuit alarms, and the digital circuit in the SIM card chip reduces the operating frequency.

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