TW492012B - Energy bandgap reference circuit with low power supply - Google Patents

Abstract

The invented energy bandgap reference circuit contains one current source, which is in proportion to the absolute temperature current (IPTAT), and the other current source, which is in proportion to the current (IPTVBE) of base-to-emitter voltage (VBE). The first terminals of both IPTAT and IPTVBE current sources are connected to a reference voltage (Vcc), and the second terminals are connected to the reference point by connecting the first resistor (RX) and the operation amplifier (OPAMP) through the reference point (REF). By using IPTAT, IPTVBE and the first resistor RX stated above, the energy bandgap and the sub-energy bandgap voltages are generated.

Description

492012 V. Description of the invention (1) Field of the invention The present invention relates to an energy gap reference circuit (bandgap r e f e r c n c e c i c u i t), especially a band gap reference circuit using a low power supply of a P T A T current source. BACKGROUND OF THE INVENTION Sub-micron process technology has been widely used to improve the performance and operation speed of integrated circuits to reduce the cost of each chip. The integrated circuit (IC) has been significantly improved in technology, and increasing the density of electronic components has become a trend. By reducing the size of electronic components, the integration density of semiconductor integrated circuits can be increased. As the size of electronic components has been reduced, integrated circuits continue to present many new challenges in the manufacturing process. For example, the reduction in the size of dynamic random memory (DRAM) cells has resulted in a reduction in storage capacitance and a lack of reliability. As the degree of accumulation of semiconductor elements increases, the area of each memory cell typically decreases. To reduce the memory cell area, several techniques have been introduced to improve the performance of the device. In particular, high-order integrated circuits have multiple interconnects to isolate the dielectric layers. When the circuit's characteristic structure is reduced, the need to reduce the resistance associated with electrical connections or contact windows will become more important than in the past. Participation In the design of very large integrated circuits, it is often necessary to provide a regional reference potential of a known value, and it can maintain stability under temperature and process changes. The most commonly used method is the so-called bandgap reference circuit, which can provide stability, accuracy, and accuracy.

492012 V. Description of the invention (2) Continuous output reference potential for various analog circuits. Basically, the bandgap voltage reference or bandgap voltage reference cell (bandgap voltage ref erence ce 1 1) includes a bipolar transistor, which is driven by an operational amplifier, and its collector is consumed by the operational amplifier. It also contains two resistors. United States Patent 6,002,293, the inventor Brokaw discloses an energy gap reference circuit, the invention name is' f H i gh transconductance voltage reference cell ". For other related previous cases, please refer to:

United States Patent 5, 798, 669, the inventor is Klughart, and the invention name is ‘’ Temperature compensated nanopower vo 1 tage / current reference 丨 丨;

United States Patent 5, 619, 163, the inventor is Koo, the name of the invention is 丨, Bandgap voltage reference and method for providing same "

United States Patent 6, 016, 051, the inventor is Can, and the invention name is 丨 丨 Bandgap reference voltage circuit with PTAT current source "; Generally, the bandgap reference circuit uses the P T A T potential, which can provide a stable zero temperature coefficient reference potential. The PTAT circuit uses the difference between the base and emitter potentials (VBE1-VBE2) as follows: Δ VBE = VBE1-VBE2 = VPTAT ⑴ Δ VBE = (kT / q) ln (Jl / J2) (2)

Page 5 492012 V. Description of the invention (3) " ~~~ " where k is the Boltzmann constant, τ is the absolute temperature of the Kelvin temperature scale, and q is the charge 'J 1 and J 2 are two electric currents flowing respectively. The current density of the crystal. Use △ v B E for the positive circuit and the proper ratio of the two resistors. See U.S. Patent No. 6016 051, see Figures 1 and 2 for a prior art bandgap reference circuit, which contains two current sources, one is IPTAT (the current that is original to the absolute temperature) and IBIAS (bias current), one of which is coupled to a voltage source (Vcc). The other end of the bias current IBI AS is connected to the emitter of the bipolar transistor. The transistor p 2 base reference terminal, the emitter is connected to the other end of the bias current IBI AS, a resistor R2 2 spans between the transistor spring P2 base and the emitter. The resistor R23 is connected between the reference potential terminal of the other end of the IPTAT and the ground terminal. Figure 2 uses the metal-oxide semiconductor transistors M 1 and M 2 as the two current sources mentioned above. In operation, the current source IPAT provides a reference current, which is a reference to the absolute temperature. I B I A S provides a bias current large enough to provide a current to the resistor R22. The current provided in the resistor R22 is proportional to the base-emitter potential of the transistor P2. However, under the general point 25 or point 18 process, the 'previous technology' cannot operate below V C C below 1. If the desired reference potential VREF is equivalent to the threshold voltage of the metal-oxide semiconductor transistor, in Figure 2, V sd (voltage between source and drain) of PM0S φ Μ 2 must be greater than vsg-I Vh, where V sg Potential between gate and source. Therefore, v s d-V s g-V t h I. If the prior art shown in Figure 1 is operational, the following conditions must be met:

Page 6 492012 V. Description of Invention (4):

Vsd, m2 (M2) + VBE + VREF < VCC However, if it is approximately equal to 0.5 volts and VBE is approximately equal to 0.5 volts, and usually, VSD, M2 (M2) + VBE + VREF > 1 volts' previous technology Cannot operate below VCC below 1. Based on the trend of reducing the operating voltage, current circuits cannot be adapted to low supply potentials. Object and Summary of the Invention: In view of the disadvantages of the prior art, the object of the present invention is to provide a bandgap reference circuit which can operate at a low supply potential. An object of the present invention is to provide an energy gap reference circuit which can provide a sub-bandgap reference circuit for operation at a low supply voltage. The energy gap reference circuit includes: a current source that is proportional to the absolute temperature current (IPTAT); a current source that is proportional to the base-emitter potential (VBE) current (IPTVBE); the first end of the above IPTAT and IPTVBE current sources Is coupled to a reference potential (Vcc), the second end is connected to the first resistor (RX) through a reference point (REF); and an operational amplifier (0ΑAMP) is coupled to the above reference point, using the above IPT AT, IPTVBE and the first A resistor RX generates an energy gap and a secondary energy gap potential.

492012 V. Description of the invention (5) The above bandgap reference circuit includes an IPTAT generating circuit for generating the above-mentioned I PTAT current. The I PTAT generating circuit includes: a first bipolar transistor coupled to a current source of IPTAT; A resistor coupled to the current source of the IPTAT; and a second bipolar transistor coupled to the second resistor. The aforementioned energy gap reference circuit includes an IPTVBE generating circuit for generating the IPTVBE current described above. The IPTVBE generating circuit includes a third bipolar electric crystal coupled to the IPTVBE current source; and a third resistor coupled to the IPTVBE current source. Detailed description of the invention: The present invention discloses a bandgap reference circuit. Please refer to FIG. 3. The architecture of the present invention includes two current sources, one is the IPT AT (current proportional to the absolute temperature) current source 2 2 0 and one is proportional to VBE current (IPTVBE) current source 210. The above-mentioned IPT AT and IPTVBE are generated using a current source (current proportional to absolute temperature) of IPT AT and a current source (IPTVBE) proportional to VBE. One end of I P T A T and IPTVBE is coupled to a reference potential (Vcc), and the other end is connected to a resistor RX through a reference point REF, and the current flowing through it is IBG. OPAMP-terminal is coupled to the above reference point, the reference potential is VREF. Using the current source of IPTAT, the current source proportional to VBE (IPTVBE), and the resistor RX, the energy gap and secondary energy gap potentials are generated. For a preferred embodiment, refer to the energy gap reference circuit 2 0 0 in FIG. 5, which includes a first metal oxide.

Page 8 492012 V. Description of the invention (6) The semi-transistor M4, in a preferred embodiment, may be a first-type transistor, and may be PMOS or NMOS. The first terminal is coupled to the reference potential Vcc 'and the terminal is coupled to the resistor RX. The gate is coupled to the IPTVBE generating circuit 400. The second metal-oxide-semiconductor transistor M 5 may be a first type transistor in a preferred embodiment, and may be a PMOS or NMOS. The first terminal is coupled to the reference potential VCC ′ and the second terminal is dissipated. For the resistor rx, the gate and the IPTAT generation circuit 3 0 0. As known to those skilled in the art, the transistors M4 and M5 mentioned above can use the first type or the second type transistors, that is, PMOS or NMOS. Those skilled in the art can use PMOS or NMOS to infer that the terminal V cdi is coupled to the terminal or source. 0 Please refer to Fig. 4. According to the embodiment of Fig. 3, the present invention uses the architecture of Fig. 4 to generate the required I PTAT current (current proportional to the absolute temperature) and the current proportional to VBE (IPTVBE). The IPT AT generating circuit 300 and the IPTVBE generating circuit 400 can generate a current proportional to the absolute temperature and a current proportional to the VBE, respectively. The addition of the above currents generates I BG, that is, the current flowing through the resistor RX. The IPT AT generating circuit 3 0 includes a current source 2 3 0 and 24 0 of the IPT AT, which are respectively incorporated in the emitter of the first bipolar transistor (Q 1) and the second bipolar transistor (q 2). An embodiment of the above-mentioned current source of I PTAT can be referred to FIG. 5. In a specific embodiment, the current source of I PTAT is composed of four metal-oxide semiconductors. The current source of the IPT AT includes the third metal-oxide semiconductor transistor M6, the fourth metal-oxide semiconductor transistor M7, the metal-metal oxide semiconductor M8, and the sixth metal-oxygen semiconductor.

Page 9 492012 V. Description of the invention (7) M 9. The third metal-oxide-semiconductor M6 and the fourth metal-oxide-semiconductor M7 can be composed of the first type of transistor. The first terminal is respectively coupled to the reference potential V cc, and the second terminal is respectively coupled to the above-mentioned one. The first metal-oxygen semi-transistor M8 and the sixth metal-oxygen semi-transistor M9 may include a second-type transistor. The other ends of the first metal oxide semi-transistor M 8 and the sixth metal oxide semi-transistor M 9 are respectively coupled to the emitters of the bipolar transistor Q2 and Q2. A resistor ΪΠ is disposed between the sixth metal-oxide semiconductor transistor M9 and the bipolar transistor Q2. In addition, the gates of the third metal-oxide-semiconductor M6 and the fourth metal-oxide-semiconductor M7 are coupled to the gate of the second metal-oxide-semiconductor M5 of the energy gap reference circuit 200, and the sixth The first end of the metal-oxide semiconductor transistor M9. The first metal oxide semiconductor M8 and the sixth metal oxide semiconductor M9i _ gate are coupled to the second end of the third metal oxide semiconductor M6. The IPTVBE generating circuit 4 0 includes a current source 2 5 0 and 2 6 0 of the IPTVBE respectively coupled to the resistor R 2 and the emitter of the third bipolar transistor (Q 3). An embodiment of the current source of the IPTVBE described above can be referred to FIG. 5. In a specific embodiment, the current source of the IPTVBE is composed of four metal-oxide semiconductors. The current source of the IPTVBE includes a seventh metal-oxide semiconductor M10, an eighth metal-oxide semiconductor M1 1, a ninth metal-oxide semiconductor M12, and a tenth metal-oxide semiconductor M13. The seventh metal-oxide semi-transistor M9 and the eighth metal-oxide semi-transistor Mil can be composed of the first type of transistor. The first terminal is respectively coupled to the reference potential V cc, and the second terminal is respectively coupled to the ninth gold. The oxygen semitransistor M 1 2 and the tenth gold oxygen semitransistor M 1 3. The other end of the ninth metal-oxide semiconductor transistor M 1 2 is coupled to the emitter of the bipolar transistor Q3, and the tenth metal-oxide semiconductor transistor M 13 is coupled to the resistor R 2. Ninth metal oxysemi-transistor M 1 2 and tenth metal oxysemi-transistor M 1 3 are available

Page 10 492012 V. Description of the invention (8)-Composition of type transistor. It is expected that the gate of the seventh metal-oxide semiconductor M9 and the eighth metal-rolled semiconductor transistor Mil are coupled to the gate of the first metal-oxide semiconductor M4 of the bandgap reference circuit 2000. The gates of the ninth metal-oxide semiconductor transistor M12 and the tenth metal-oxide semiconductor transistor M13 are coupled to the terminals of the seventh metal-oxide semiconductor transistor M13. According to the configuration of the present invention and referring to FIG. 4, the IpTAm generating circuit 3 0 0: The IPTAT generating circuit 3 0 0 has the potential of the emitter terminal Q1 as VBE1 (the potential between the emitter and the base), and the bipolar transistor emits light. The extreme potential is VBE2 (potential between emitter and base). In the IpTVBE generating circuit 400, the potential of the emitter terminal of the bipolar transistor Q3 is VBE (the potential between the emitter and the base). In the IPTAT generating circuit 3 0 0: VBE 1 (Q-electrode base potential) = vt 1 η (IC1 / I S1) VBE 2 (Q 2 emitter-base potential): = vt 1 n (Bu i IPTAT potential (VPTAT) ·· VPTAT = VBE and VBE2 = Z \ VBE = Vt ln (Icl Is2 / Isi Ic2), where ln (ICl IS2 / IS1 IC2) is a constant. Therefore, the potential of jpTAT VPTAT is at It is a constant at a specific absolute temperature. In Figure 4, 'IPTAT is a current source whose current density is proportional to the absolute temperature of 4 degrees. The base-emitter potential of the bipolar transistor Q3 is VBE. Its operation is described by the following formula: No .: IBG = I1 + I2 in Figure 3, where Il = ipTAT, I2 = VBE / R2 = IPTVBE, which is proportional to the current of VBE.

492012 V. Description of the invention (9) Moreover, referring to FIG. 4 IPTAT generating circuit 300, VPTAT = Z \ VBE: ΙΡΤΑΤ = ΔVBE / R1-VPTAT / R15 ΔVBE = VBE1-VBE2 Therefore, the energy gap reference current can be described by the following equation: IBG = IPTAT + (VBE / R2) = (VPTAT / R1) + (VBE / R2) = (VBE + VPTATx R2 / R1) / R2 According to Ohm's Law: IBGx R2 = (VBE + VPTATx R2 / R1) makes VBG = ( VBE + VPTATx R2 / R1), that is, IBG = VBG / R2 VREF-IBGx RX = VBGx RX / R2. Therefore, the present invention can control the configuration of RX / R2, and the required reference potential VCC is greater than that of the first metal oxygen half transistor M5. The potential between the source and the drain plus VREF, so the required VCC is smaller than in the prior art (the prior art V and CC need to be greater than Vsd, m2 (M2) + VBE + VREF, see background description), so the present invention can get a low power supply Band gap reference potential or secondary band gap reference potential. To sum up, the present invention is characterized by using the circuit structures of Fig. 3, Fig. 5 and Fig. 5 to obtain a low-gap reference potential or a sub-gap reference potential. The invention has the characteristics of easy implementation and improvement of electrical properties. _ Although the present invention is illustrated by examples, those skilled in the art will know that changing the doping type of the above-mentioned transistor is also included in the spirit of the present invention. Although the present invention has been described above with reference to a preferred embodiment, it is not intended to limit the present invention.

Page 12 492012 V. Description of the invention (ίο) The spirit of the invention and the entity of the invention are limited to this embodiment, and those skilled in the art can make some modifications and modifications without departing from the spirit of the invention. The scope of patent protection depends on the scope of patent application and its equivalent fields.

Page 13 492012 Brief description of the diagram Brief description of the diagram: 'Figure 1 shows a schematic diagram of the prior art bandgap reference circuit. Figure 2 shows a schematic diagram of the prior art bandgap reference circuit. Figure 3 shows a schematic diagram of the bandgap reference circuit of the present invention. Figure 4 shows a schematic diagram of the bandgap reference circuit of the present invention. Figure 5 shows a schematic diagram of the bandgap reference circuit of the present invention. Figure number reference band gap reference circuit 2 0 0 φ current source proportional to VBE current (IPTVBE) 210 IPTAT (current proportional to absolute temperature) current source 220 IPTAT current source 2 3 0, 240 IPTVBE current source 2 5 0, 260 IPTAT generating circuit 300 IPTVBE generating circuit 400 Three metal oxide semi-transistor M6 Fourth metal oxide semi-transistor M7 First metal oxide semi-transistor M8 Sixth metal oxide semi-transistor M9 _ seventh metal oxide semi-transistor M10 Eighth metal oxysemiconductor M 11 Ninth metal oxysemiconductor Ml 2 Tenth metal oxysemiconductor M13

Page 14 492012 Brief description of the diagram Resistors RX, ΙΠ, R2 Bipolar transistors Q2 Q2, Q3 1HII111 Page 15

Claims (1)

492012 6. Scope of patent application 1 · An energy gap reference circuit, including: a current source proportional to the absolute temperature current (IPTAT); a current source proportional to the base-emitter potential (VBE) current (IPTVBE), the above-mentioned IPTAT The first terminal of both the IPTVBE and the IPTVBE current source is coupled to a reference potential (Vcc), and the second terminal is connected to the first resistor (RX) via a reference point (rEF); and the operational amplifier (OPAMP) is coupled to the above reference point Using the above-mentioned I PTAT, I PTVBE and the first resistor, an energy gap and a secondary energy gap potential are generated. 2. The bandgap reference circuit according to item 1 of the patent application scope, which includes a first metal-oxide semiconductor transistor coupled between the reference potential (Vcc) and the first resistance (RX) to control the proportionality to the base Current between emitters (IPTVBE). 3. The bandgap reference circuit according to item 2 of the patent application, wherein the first metal-oxide semiconductor is the first type metal-oxide semiconductor. 4 · The bandgap reference circuit of item 1 of the scope of the patent application, which includes a first metal-oxide semiconductor transistor coupled between the reference potential (Vcc) and the first resistance (RX) to control the proportional to the absolute temperature Current (IPT AT) current. 5. The bandgap reference circuit according to item 4 of the patent application, wherein the second metal-oxide semiconductor is the first type metal-oxide semiconductor. Page 16 492012 6. Scope of patent application 6. The bandgap reference circuit of item 1 of the scope of patent application includes an IPTAT generating circuit for generating the above IPTAT current, including: a first bipolar transistor coupled to the A current source of I PTAT; a second resistor coupled to the current source of the IPTAT; and a second bipolar transistor coupled to the second resistor. 7. The bandgap reference circuit according to item 6 of the scope of patent application, wherein the above-mentioned IPTAT generating circuit includes a third metal oxide semi-transistor, a fourth metal oxide semi-transistor, a second metal oxide semi-transistor and a sixth metal oxide semi-transistor. A transistor, wherein the first terminal of the third metal-oxide semiconductor transistor and the fourth metal-oxide semiconductor transistor are respectively coupled to the reference potential (VCC), and the second terminals are respectively coupled to the first metal-oxygen semiconductor. And the sixth metal-oxide semiconductor; the first metal-oxygen semiconductor and the sixth metal-oxygen semiconductor are coupled to the emitters of the first and second bipolar transistors, respectively, and the second resistor is disposed in the second resistor The sixth metal-oxide semiconductor transistor and the second bipolar transistor; wherein the gates of the third metal-oxide semiconductor transistor and the fourth metal-oxide semiconductor transistor are coupled to the first section of the energy gap reference circuit. The gate of the second metal-oxide semiconductor transistor, the gate of the first metal-oxide semiconductor transistor and the sixth metal-oxide semiconductor transistor are coupled to the second end of the third metal-oxide semiconductor. 8. The bandgap reference circuit according to item 8 of the scope of patent application, wherein the third metal oxide semiconductor and the fourth metal oxide semiconductor are first type metal oxide semiconductors. Page 17 492012 6. Scope of patent application 9. For example, the band gap reference circuit of item 8 of the scope of patent application, wherein the first metal-oxygen semi-transistor and the sixth metal-oxygen semi-transistor are the second type metal-oxygen semi-transistor. Transistor. I 0. The bandgap reference circuit according to item 1 of the patent application scope, which includes an IPTVBE generating circuit for generating the IPTVBE current, including a third bipolar transistor coupled to the current source of the IPTVBE; and A resistor is coupled to the current source of the IPTVBE. II. The bandgap reference circuit of item 6 of the patent application range, wherein the above-mentioned IPTVBE generating circuit includes a seventh metal oxide semi-transistor, an eighth metal oxide semi-transistor, a ninth metal oxide semi-transistor and tenth metal oxide A semi-transistor; wherein the first end of the seventh metal-oxide semi-transistor and the eighth metal-oxide semi-transistor are respectively coupled to the reference potential VCC, and the second end is coupled to the ninth metal-oxygen semi-transistor and A tenth metal-oxide semiconductor, the other end of the ninth metal-oxide semiconductor is coupled to the emitter of the third bipolar transistor, and the tenth metal-oxide semiconductor is coupled to the third resistor; And the gate of the seventh metal-oxide semiconductor transistor and the eighth metal-oxide semiconductor transistor are connected to the energy-gap reference circuit of the first metal-oxide semiconductor transistor. Bandgap reference circuit of the range item 11 in which the above Page 18 492012 VI. Scope of patent application The seventh metal-oxide semiconductor and the eighth metal-oxide semiconductor are the first type metal-oxide semiconductor. 1 3 · The bandgap reference circuit according to item 11 of the patent application, wherein the ninth metal-oxide semiconductor and the tenth metal-oxide semiconductor are the second type metal-oxide semiconductor. I Page 19