TW589790B - Soft start circuit - Google Patents

Abstract

The present invention is related to a kind of soft start circuit. The invention includes the followings: one current source; the first current mirror; the second current mirror; the first metal oxide semiconductor field effect transistor (MOSFET); the second MOSFET; and one capacitor. By using the connection of the first current mirror, the first MOSFET, the second current mirror and the second MOSFET and the capacitor, the ratio of soft start voltage to time generated from the soft start circuit is reduced so as to increase the equivalent capacitance value of the capacitor such that the soft start circuit is capable of being manufactured by a capacitor having a smaller capacitance value.

Description

589790

V. Description of the invention (l) The technical field to which the invention belongs is a soft start circuit that can increase the soft start current to a smaller capacitance value, especially the equivalent capacitance value of the circuit, so that the soft start circuit capacitance To make. Prior art

The principle of the soft-start circuit is to use a (RC) charging circuit to lightly connect a control circuit, and immediately after the load is connected, the control circuit can flow through the negative The current increases at a relatively slow rate, which means that the current through the load can be controlled to reduce the damage to the load and other coupling circuits caused by the large current generated when the power supply is connected to the load. A conventional soft-start circuit is shown in the first figure. The soft-start circuit 10 is composed of a fixed current source 11 and a capacitor 丨 2, and a series node between the current source 11 and the capacitor 12 A as the section under test for soft-start voltage

Point 0

Suppose that the current of source 11 is I, the soft-start voltage of series node a is V (Sft-start) and the capacitance value of capacitor 12 is c, according to the formula Ks〇ft — start) / T = I / C

It can be seen that, because the current I is a fixed value, if the soft-start voltage V (so ft-start) is fixed, a small v (soft-start) / T is desired.

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Ratio, the capacitance value of the capacitor 12 needs to be sufficient to satisfy. If the current common capacitor value suitable for this type of circuit is in the range of InF ~ 0 · luF, if the capacitance volume corresponding to this capacitance value is placed in a general electrical appliance circuit, and It is no problem to use an external capacitor to operate. However, if you want to use this technology in Integrated CirCUits (IC), the following two difficulties will occur: 1. The capacitor with the above-mentioned electric valley value is too large. , Can not be integrated into the integrated circuit manufacturing process, so it can not meet the trend of integrated circuit volume shrinking 2 · If you want to match the integrated circuit manufacturing process size requirements of the capacitor 'its capacitance value is not large enough It is enough to make use of the soft-start circuit I'Q Shiding tJ% Λϊ- ^ 'The applicant was informed that this case has finally been invented in this case: "Soft start of heart test, the circuit configuration of the dynamic voltage and time. In view of the bottlenecks in the conventional technology, And research, and a spirit of perseverance, and moving circuits. " The following is a brief description of this case. Summary of the Invention The main purpose of this case is to design a soft-start circuit that can reduce the soft-start 589790 generated from the soft-start circuit. 5. The ratio of the invention description (3) 'enlarges the effective value of the capacitance contained in the soft-start circuit, so that The soft-start circuit can be made with the capacitor with a smaller capacitance value (that is, a smaller volume). According to the idea of the present case, a soft-start circuit is proposed, which includes: a first current source whose input terminal is connected to a first voltage; a transistor whose first terminal is connected to the output terminal of the first current source, A second end thereof is connected to a second voltage; and a capacitor, one end of which is connected to the output terminal of the first current source and the other end of which is connected to the input terminal of the transistor; the coupling between the transistor and the capacitor is used Then, the ratio of the soft-start voltage and time generated from the soft-start circuit is reduced to increase the equivalent capacitance of the capacitor, so that the soft-start circuit can be made with the capacitor with a smaller capacitance. According to the above concept, the first current source is a current mirror. According to the above-mentioned concept, the current mirror is formed by coupling two identical P-type semiconductor half field effect transistors (MOSFETs). Electric second ίί! Think of ‘where the input end of the current mirror is connected to the second-end: terminal, and; electricity,’ this! The output of the flow mirror is connected to the voltage of the transistor. The common source terminal of the mirror is connected to the first terminal, and the output terminal of the second current source is connected to the second voltage according to the above concept. According to the above idea According to the above idea Transistor (BJT). According to the above concept, the first terminal of the transistor is the set terminal,

589790 V. Description of the invention (4) —— The second terminal of the transistor is the emitter terminal, and the control terminal of the transistor is the base terminal. According to the above concept, the t-crystal system is a Darlington transistor. 3 The above concept 'wherein the Darlington transistor is formed by a first-type carrier-junction transistor and a first-division unit, and Xi Chu-i-npni and carrier-junction transistor are coupled日 日 ^ ηΡη The base terminal of the saint-type double-junction junction transistor is the capacitor, the type of double-junction junction transistor == _type double-junction junction transistor terminal, the first-? Junction junction The set of crystals is connected to form a second connection =: the second terminal of the 'pn-type bipolar junction transistor is the first extreme of the transistor. A soft-start circuit having a package mirror whose input terminal is connected to the current transmission source of the current source 1: the-current extreme terminal is connected to the second electric (HyH_OSFET), and the source common gate terminal thereof;-the second The metal-oxygen half-field effect is connected to the order of the 5th Hai-current mirror, one end of which is connected to the first voltage of the first current mirror; a field-effect transistor has no extremes, and the other end and the second gold The extremes of the oxygen half-transistor; and the drain terminal of the second metal-oxide-semiconductor field-effect half-field-effect transistor, the input terminal of which is connected to its common source terminal and 589790 V. Description of the invention (5) '' ----- a voltage whose output end is connected to the other end of the capacitor and the gate end of the second metal-oxide-semiconductor half-effect transistor; using the first current mirror, The coupling of the first metal-oxide half-efficiency power transistor, the second current mirror, and the second metal-oxide half-effect transistor with the capacitor reduces the soft-start electric friction and time generated by the soft-start circuit. The ratio is used to increase the equivalent capacitance of the capacitor, so that the soft-start circuit can be made with the capacitor with a smaller capacitance. According to the above concept, wherein the first voltage is smaller than the second voltage. According to the above concept, the first current mirror is formed by lightly connecting two identical P-type metal-oxide-semiconductor half field effect transistor transistors. / According to the above concept, the first metal-oxide-semiconductor field-effect transistor is a -P metal-oxide-semiconductor field-effect transistor, and the channel aspect ratio is smaller than the first P-metal-oxide-semiconductor half-field effect The aspect ratio of the channel region of the effect transistor. According to the above concept, the second metal-oxide-semiconductor field-effect transistor is an N-type metal-oxide-semiconductor field-effect transistor. According to the above concept, the second current mirror is formed by coupling a first N-type MOSFET and a second N-type MOSFET. According to the above concept, wherein the drain of the first N-type metal-oxide-semiconductor field-effect transistor is the input of the second current mirror, the second N-type metal-oxide-semiconductor field-effect transistor is > Output. According to the above-mentioned concept, the channel region width-length ratio of the first N-type metal-oxide-semiconductor field-effect transistor is larger than the channel region of the second N-type metal-oxide-semiconductor field-effect transistor 589790

Aspect ratio. A soft start circuit is provided by an electric weeper, which includes a motor source, whose output terminal is connected to a first thunderbolt · a # mirror, and its input terminal is connected to _ 雷 哭 $, the first current Yu-Second Voltage · First Current ^^ Λ " ^ Yi Lei said that the hybrid dairy cow cuts the electric sun-solar body, whose drain terminal is connected to the drain terminal of the -B body, and its source terminal is connected to the first One end of the voltage · 1 ^ is connected to the drain terminal and the first terminal of the first metal-oxide-semiconductor half field-effect transistor, and the other end of the voltage-loss half-field transistor is connected to the gate of the second metal-oxide-semiconductor half-effect transistor. An extreme end; and a second current mirror whose input end is connected to the output end of the first current mirror, its common source end is connected to the first voltage, and its output end is connected to the other end of the capacitor and the second metal oxide The gate extreme of the half field effect transistor; the coupling between the first current mirror, the first metal oxide half field effect transistor, the second current mirror, and the second metal oxide half field effect transistor and the capacitor is reduced, The ratio of the soft-start voltage ^ time generated by the soft-start circuit to increase the equivalent power of the capacitor The capacitance value enables the soft & dynamic circuit to be fabricated with a smaller capacitance value of the capacitor. According to the above concept, wherein the first voltage is smaller than the second voltage. According to the above concept, wherein the first current mirror is coupled by a p-type metal-oxide half-field effect transistor and a second P-type metal-oxide half-field effect transistor, and according to the above-mentioned concept, wherein the first P-type metal oxide The drain of the half field effect transistor is the input of the first current mirror, and the second P-type metal-oxide half field effect transistor

589790

5. Description of the invention (7) The drain of the crystal is the output terminal of the first current mirror. According to the above-mentioned concept, wherein the aspect ratio of the channel region of the first P-type metal-oxide-semiconductor half-field-effect transistor is larger than that of the second p-type metal-oxide-semiconductor half-field-effect transistor. According to the above concept, wherein the first metal-oxide-semiconductor half-field-effect transistor is a p-type metal-oxide half-effect transistor. According to the above-mentioned concept, 'wherein the second metal-oxide half-field-effect transistor is an N-type metal-oxide-semiconductor field-effect transistor. According to the above concept, the second current mirror is formed by coupling a first N-type gold gas half field-effect transistor and a second N-type metal-oxygen half field effect transistor. According to the above concept, wherein The sum of the first N-type metal-oxide-semiconductor field-effect transistor and the input terminal of the second current mirror, and the draw of the second N-type metal-oxide-semiconductor field-effect transistor are the wheel output of the second current mirror. It is envisaged that the width-to-length ratio of the forcing region of the first N-type metal-oxide-semiconductor field-effect transistor is larger than the channel-length ratio of the channel region of the second N-type metal-oxide-semiconductor field-effect transistor.,

The case has to be understood in more depth through the following drawings and detailed description:

10th stomach 589790 V. Description of the invention (8) Please read the second picture, which is the first preferred implementation picture of this case. As shown in the second figure, the second system of the soft-start circuit is π = ": mirror 22, capacitor 23, and npn type bipolar junction transistor ^ 。. Among them, the current mirror 22 is composed of two identical p-types Metal oxide half field effect transistors (M0SFET) 221 and 222 are coupled, and the p-type metal oxide half field effect transistors 22 1 and 222 have gate terminals connected to each other, source terminals connected to high voltage 25 ′, and P The drain terminal of the metal oxide semiconductor field effect transistor 221 forms the input terminal of the current mirror 22, and the drain terminal of the P metal oxide semiconductor field effect transistor 222 forms the output terminal of the current mirror 22. In addition, the input terminal of the current mirror 22 Connected to the input of the current source 21, the output of the current mirror 22 is connected to one of the capacitor 23 and the collector of the npn type bipolar junction transistor 24, and the other end of the capacitor 23 is connected to the 叩 n type double The base terminal of the carrier junction transistor 24, the output terminal of the current source 21 and the emitter terminal of the ηρη-type bi-carrier junction transistor 24 are connected to the low voltage 26. As can be seen from the second figure, the current source 2 The constant current generated (assuming its size is Γ) is mapped by the current mirror 22, so that the self-junction of the ηρη type The magnitude of the current flowing out of the emitter terminal of the crystal 24 is also 丨. Due to the element characteristics of the ηρη-type double-carrier junction transistor, the current flowing into the base terminal of the ηρη-type double-junction transistor 24 flows into nprl. The current at the collector terminal of the ambipolar junction transistor 24 and the current flowing out of the emitter terminal of the npri ambiode junction transistor 24 have a proportional relationship with each other. 丨: b: (b + 1), so The current of the capacitor 23 (that is, the current flowing into the base terminal of the ηρη-type bipolar junction transistor 24) is I '/ (b + i). When b is large enough (with modern ηρη-type bicarriers) The interface transistor is usually between 100 and 20 0), which can flow through the capacitor 23

P.11 589790 V. Description of the invention (9) The current is regarded as γ / b. Substituting this γ / b value into the current I at the formula v (sofbu start) / T = I / r, we can get V (soft-start) / T = (I, / b) / C, which can also be regarded as V (soft-start) / T = Γ / (bC).

It can be seen that when the soft-start voltage V (soft —start) is fixed, a small V (S0ft-start) / τ ratio is desired. If the soft-start circuit described in this case is used, the capacitance of the capacitor 23 can be adjusted. The effective capacitance value is enlarged by 1), so that one can use a capacitor with a small capacitance value to make a soft-start circuit with a sufficiently small soft start voltage and time ratio (V (soft-start) / T).

Please refer to the second figure ', which is a schematic circuit diagram of a soft start circuit according to a second preferred embodiment of the present invention. As shown in the third figure, the soft start circuit 30 is a current source 31, a current mirror 32, a capacitor 33, and a DarUngtc transistor 34. Among them, the current mirror 32 is formed by coupling two identical P-type MOSFETs 321 and 322, and the gate ends of the p-type MOSFETs 321 and 322 are connected to each other and the source is prostituted. Connected to high voltage 35, and P-type CMOS half field effect transistor 321 = terminal: J

The input terminal of the current mirror 32 and the drain terminal of the P-type MOSFET half-effect transistor 322 form the output terminal of the current mirror 32. In addition, the Darlington transistor 34 is composed of two identical npn-type junction junction transistors 341 and 342. The base terminal of the npn-type junction junction transistor 341 is Darlington. Input terminal of transistor 34, the collector terminals of npn type double # sub-junction transistor 3 41 and 3 4 2 are connected to each other and connected to NVC & SEM

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npn type double # + m2 The emitter terminal of the carrier junction transistor 341 is connected to the output terminal of 32, 11011 is scraped off 2 &Γ; the base terminal of the H-plane electric sun and sun body 342, a chat type double carrier The emitter terminal of the junction transistor 342 is connected to a low voltage%. & Carrier interface electric steam H: The input terminal of the mirror 32 is connected to the input terminal of the current source 31, the == wheel output terminal is connected to one terminal of the capacitor 33 and ηρη double-sided, the common set of the bodies 341 and 342 The other end of the capacitor 33 is connected to the input of the triode 34, and the output of the current source 31 is also connected to

It can be seen from the third figure that the constant current generated by the current source 31 (assuming its large ^ is mapped by the current mirror 32, so that the ηρη-type double-carrier junction

Electricity = The current flowing out of the emitter of body 342 is also 丨 ,,. Due to the characteristics of the Darlington electric body (assuming that the current ratio of the collector 基 to the base terminal of the thunder-type double-junction junction transistor 34 is b, the npn-type double-junction junction transistor 342 is also Same), so that the current flowing into the base terminal of the npn type bipolar junction transistor 34ι and the current flowing out of the emitter terminal of the npn bipolar junction transistor 342 have a proportional relationship with each other 1: (b + 1 ) 2, so the current flowing through the capacitor 3 3 (that is, the current flowing into the base terminal of the npn type bipolar junction transistor 341) is I ″ / (b + l) 2, when b is large enough (For modern npn type bipolar junction transistor, it is mostly between 1000 and 2000), the current flowing through the capacitor 33 can be regarded as Γ '/ 1) ¾. Substituting this value of Γ, / b2 into the current I at the formula V (soft-start) / Ί = l / C, we can get V (soft-start) / T = (I ,, / b2) / C. See also to make

Page 13 589790 V. Description of the invention (11) V (sof t ~ start) /

T (b2C) Γ. It can be seen that when the soft-start voltage V (soft-start) is fixed, a small V (so ft-start) / T ratio is desired. If the soft-start circuit described in this case is used Can multiply the equivalent capacitance value of capacitor 23 from multiples, so that we can use a capacitor with a very small capacitance value to make a soft-start circuit with a sufficiently small soft-start voltage to time ratio (V (sof t-start) / Τ). . Refer to the fourth figure, which is a schematic circuit diagram of the soft-start circuit of the third preferred embodiment of the present invention. The difference from the first and second preferred embodiments is that a preferred embodiment is a complementary metal The circuit layout of the oxygen CMOS process. As shown in the fourth figure, the soft-start circuit 40 is composed of a current source 41, three P-type MOSFETs (42, 43, and 44), and three N-type MOSFETs (45, 46). And 47) and a capacitor. Among them, the channel aspect ratio of the p-type metal-oxide-semiconductor half field-effect transistors 42 and 44 is identical to each other, but the > sections are all P-type metal-oxide semi-effect transistors. A multiple of the channel width-to-length ratio of 43 (assuming η times). The channel width-to-length ratio of the N-type metal-oxide-semiconductor field-effect transistor 45 is a multiple of the N-type metal-oxide-semiconductor field-effect transistor 46 (assuming ^ times). In the fourth figure, the source terminals of P-type metal-oxide-semiconductor half-effect transistors 42, 43 and 44 are all connected to high-voltage 491, and the gates of the three are connected to each other and a total of 5 short-circuits with p-type metal-oxide-semiconductor half-effect transistor The drain terminal of the crystal, and the drain terminal of the p-type gold :: effect crystal 42 is connected to the input terminal of the current source 41, and the output terminal of the electric two 1 is connected to the low voltage 49 2. Therefore, see, the golden lice half field effect transistors 42 and 44 also form a current map together.

) Silicon 79〇

Current mirror with 1 magnification. ^ IV: The metal-oxide half field-effect transistor 45 is short-circuited by the gate and the drain terminal. The light-source half-field transistor 43 is connected to the drain terminal, and the N-type full-field-effect transistor 45 is connected to the common gate terminal. This method is composed of N-type metal-oxygen half-field ^ gold = body 46-a current mirror with a current mapping magnification of 1 / m. The common source is connected to the low voltage 492. /, '

Finally, the drain terminal of the N-type metal-oxide-semiconductor half-field-effect transistor 47 and the capacitor 48 = 鳊 are connected to the drain terminal of the P-type metal-oxide-semiconductor half-field-effect transistor 44 and the gate terminal of the n-type metal-oxide-semiconductor half-field-effect transistor 47 and The other end of the capacitor 48 is connected to the drain terminal of the N-type metal-oxide-semiconductor field-effect transistor 46 after a short circuit, and the source terminal of the N-type metal-oxide-semiconductor field-effect transistor 47 is also connected to the low voltage 492. From the fourth figure, it can be seen that the constant current generated by the current source 41 (assuming its size is Γ '') is mapped by a current mirror composed of P-type metal-oxide-semiconductor field-effect transistors 42 and 44. The current flowing from the drain terminal of the metal-oxygen half field effect transistor 44 is also Γ ,,.

In addition, the mapping of the current mirror composed of the P-type MOSFETs 42 and 43 makes the current flowing from the drain terminal of the P-type MOSFETs 43 to be I ′ '/ η. Then through the mapping of a current mirror composed of N-type metal-oxide-semiconductor half-field-effect transistors 45 and 46, the magnitude of the current flowing into the collector extreme of N-type metal-oxide-semiconductor half-field-effect transistor 46 becomes I ,,, / (mn) . Since the current flowing into the gate terminal of the N-type metal-oxide-semiconductor half-field-effect transistor 47 is extremely small compared with 丨 ,,, / (mn), the magnitude of the current flowing through the capacitor 48 can be regarded as ,,,,, / (mn) 〇As a result of (1) flowing from the drain terminal of the P-type metal-oxide half-field-effect transistor 44

Page 15 589790 V. Description of the invention (13) The magnitude of the current is Γ '' (2) The magnitude of the current flowing through the capacitor 48 is regarded as Γ, and / (mn) 'and when m & n is large enough (in modern Metal-oxygen half field effect transistors are mostly above 25), the current value flowing through the capacitor 33 丨 ,,, / (mn) is substituted into the current I at the formula V (soft-start) / T = I / c. We get V (soft-start) / T = (I ,,, / mn) / C, which can also be regarded as V (soft-start) / T = I ,, / (mnc).

It can be seen that when the soft-start voltage v (s〇ft —start) is fixed, I want to get a smaller V (S0ft-start) / T ratio. If the soft-start circuit of this case is used, The equivalent capacitance value of the capacitor 23 is enlarged by a factor of two, so that people can use a capacitor with a very small capacitance value to make a soft-start circuit with a sufficiently small soft-start voltage and soft-start ratio (V (soft-start) / T).

From the above three preferred embodiments, it can be known that the way the soft-start circuit is set in this case can amplify the effective value of the capacitor, so that when I make a soft-start circuit, I can have a smaller capacitance value (that is, a smaller volume). Capacitance is 1 to achieve a small soft start voltage to time ratio, which is to reach a slow increase rate of the current through the load, making the system more queen-like at startup; especially the softness of the third preferred embodiment. The start-up circuit is based on the c ^ ios process as the implementation environment of the circuit. The capacitor can be produced with the requirements of the process size of the integrated circuit, and the f-type configuration described in this case makes the effective capacitance sufficiently large. It can play the protection function of the soft-start circuit, so it can be effectively integrated into the manufacturing process of integrated circuits, which is in full compliance with the world trend of increasingly smaller integrated circuits. That is why this case is indeed able to ς 589790

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Brief description of the drawings Brief description of the drawings The first diagram: a schematic circuit diagram of a conventional start-up circuit ^ & ^ a circuit diagram of a soft-start circuit of the first preferred embodiment of the case; the second diagram: the case A schematic circuit diagram of the soft start circuit of the second preferred embodiment; and a fourth diagram: a circuit schematic diagram of the soft start circuit of the third preferred embodiment of this case. Φ The components included in the scheme of this case are listed as follows:

Soft-start circuits 10, 20, 30, 40 Current sources 11, 21, 31, 41 Current mirrors 22, 32 Capacitors 12, 23, 33, 48 npn bipolar junction transistor 24, 341, 342 P-type metal oxide Half field effect transistors 221, 222, 321, 322, 42, 43, 44 High voltage 25, 35, 491 Low voltage 26, 36, 492 Darlington transistor 34 N-type metal oxide half field effect transistor 45, 46, 47

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Claims (1)

'Applicable patent scope h — a start-up circuit including: a first current source whose input terminal is connected to a first voltage · a transistor whose first terminal is connected to the first mine, taxi, ... / Terminal, a second terminal of which is connected to a second voltage; and electric muscle, the original wheel out-capacitor, one end of which is connected to the output terminal of the first current source, and connected to the input terminal of the transistor; It also uses the coupling of the transistor and the capacitor to reduce the ratio of the soft-start voltage and time of the Baixi private battery, thereby increasing the value of Xilei slightly six from the Japanese knives. The soft-start circuit can be made in a smaller size. The capacitor of the combined value 2. The soft-start circuit as described in item 1 of the scope of patent application, wherein the first current source is a current mirror. 3. The soft-start circuit as described in item 2 of the scope of patent application, wherein the current mirror is coupled by two identical P-type metal-oxide-semiconductor field-effect transistors (MOSFETs) to form 0. 4 · The soft-start circuit according to item 3 of the scope of patent application, wherein the input end of the current mirror is connected to the input end of a second current source, and the output end of the current mirror is connected to the first end of the transistor. And one end of the capacitor, the common source terminal of the current mirror is connected to the first voltage. 5. The soft-start circuit according to item 4 of the scope of patent application, wherein the wheel output of the second current source is connected to the second voltage. 6. The soft-start circuit according to item 1 of the scope of patent application, wherein the first voltage is greater than the second voltage. 7 · The soft-start circuit as described in item 1 of the patent application scope, wherein the transistor 6. Scope of patent application The body is an nPn type bipolar junction junction transistor (BJT). Body 8 :: The soft-start circuit described in item 7 of the scope of profit, wherein the transistor is a set terminal, the second terminal of the transistor is an emitter terminal, and the control terminal of the μ-electron sun body For the base extreme. ^ The soft-start circuit described in item i of the scope of the patent application is a Darlington transistor (DarlingtQn transist). The soft-start circuit described in item 9 of the scope of the patent application, wherein the transistor is diagnosed From a first npn-type double-carrier junction transistor and two X 2 transistors, Lin Xi's technology is coupled to the first extreme pole of the nPn-type double-junction transistor: Type = the base extreme, the first ιρη-type double-junction junction transistor; ί?: = Ηρη-type double-junction junction transistor is formed to form the extreme end; The extreme is the shot of the second bipolar junction transistor of the transistor11. A soft-start circuit comprising: a current source, the wheel output of which is connected to a first voltage; The metal Λ half-gate 1-effect Λ crystal (M0SFET) has its source terminal connected; the terminal voltage is connected to the common closed pole of the first current mirror and the output terminal of the first metal-oxide half field effect transistor current mirror. Its source; Ge Qi's drain is connected to the first-May I be connected to the first voltage; 589790 A capacitor, one end of which is connected to the output terminal of the first current mirror and the drain terminal of the first metal-oxide-semiconductor field-effect transistor, and the other end of which is connected to the gate terminal of the second metal-oxide-semiconductor field-effect transistor; and The two current mirrors have an input terminal connected to the drain terminal of the first metal-oxide half-field-effect power source, a common source terminal connected to the first voltage, and an output terminal connected to the other end of the capacitor and the second power source. The gate of the crystal; 々, using the first current mirror, the first metal-oxide-semiconductor field-effect transistor, the coupling between the first current mirror and the second metal-oxide-semiconductor field-effect transistor, and the capacitor to reduce the The ratio of the soft-start voltage and time generated by the startup circuit increases the equivalent capacitance value of the capacitor, so that the soft-start circuit can be made with the capacitor with a smaller capacitance value. 1 2 The soft-start circuit according to item 11 of the scope of patent application, wherein the first voltage is smaller than the second voltage. 1 3 · The soft-start circuit according to item 11 of the scope of patent application, wherein the first current mirror is formed by coupling two identical first p-type metal-oxide-semiconductor half-effect transistor transistors. 1 4 · The soft-start circuit as described in item 13 of the scope of patent application, wherein the first metal-oxide-semiconductor field-effect transistor is a P-type metal-oxide-semiconductor field-effect transistor, and its channel area width (length) ratio ( The aspect ratio is smaller than the channel area aspect ratio of the first p-type CMOS half field effect transistor. 15 · The soft-start circuit according to item 11 of the scope of patent application, wherein the second metal-oxide-semiconductor field-effect transistor is an N-type metal-oxide-semiconductor field-effect transistor. 16 · The soft-start circuit as described in item 15 of the scope of patent application, wherein the second current mirror is composed of a first N-type metal-oxide-semiconductor field-effect transistor and a second N-type gold Page 21 589790 6. Scope of patent application The oxygen half field effect transistor is coupled. 17 · The soft-start circuit as described in item 16 of the scope of patent application, wherein the first N-type metal-oxide half-field effect transistor and the input terminal of the first current mirror, the second N-type metal-oxide The drain of the half field effect transistor is the output of the second current mirror. 18 · The soft-start circuit according to item 16 of the scope of patent application, wherein the channel area width-length ratio of the first N-type metal-oxide-semiconductor half-effect transistor is larger than the channel region of the second N-type metal-oxide-semiconductor half-effect transistor Aspect ratio. 19. · A soft-start circuit including: 'A current source whose output is connected to a first voltage; a first current mirror' its input is connected to the input of the current source 'and its common source terminal is connected to a second voltage; ▲ a first metal oxide A half field-effect transistor (M0SFET) whose source terminal is connected to the second voltage of 50 Hz, and whose gate terminal is connected to the common gate electrode of the first current mirror; The source terminal of the first oxygen half field effect transistor is connected to a first source terminal of the first electric power point, which is connected to the child's gold metal half field effect transistor. The drain terminal of the crystal has its other end connected exclusively to the gate terminal of the second metal-oxide-semiconductor field-effect transistor; and the input terminal of the output terminal connected to the first current mirror is connected to the first voltage. The output end is connected to the cable; the extreme between the second metal-oxide-semiconductor field-effect transistor; I current mirror, the first metal-oxide-semiconductor field-effect transistor, the 589790, the patent application scope of the second current mirror, and the second metal The coupling of the oxygen half field effect transistor and the capacitor 'is reduced since the soft start The ratio of the soft-start voltage and time generated by the dynamic circuit increases the equivalent capacitance of the capacitor, so that the soft-start circuit can be made with a capacitor with a smaller capacitance. 20. The soft-start circuit according to item 19 in the scope of the patent application, wherein the first voltage is smaller than the second voltage. 21 · The soft-start circuit as described in item 19 of the scope of the patent application, wherein the first current mirror is coupled by a first P-type metal-oxide-semiconductor and a second P-type metal-oxide-semiconductor. Made. 22. The soft-start circuit as described in item 21 of the scope of patent application, wherein the drain of the first P-type metal-oxide-semiconductor half-effect transistor is the input of the first current mirror, and the second P-type metal-oxide-semiconductor half-effect transistor The drain of the crystal is the output of the first current mirror. 2 3 · The soft-start circuit as described in item 22 of the scope of patent application, wherein the channel aspect ratio of the first P-type metal-oxide-semiconductor half-effect transistor is greater than the second P-type gold Channel area aspect ratio of oxygen half field effect transistor 0 24. The soft-start circuit according to item 23 of the scope of the patent application, wherein the first metal-oxide-semiconductor field-effect transistor is a P-type metal-oxide semi-effect transistor. 2 5 · The soft-start circuit as described in item 19 of the scope of patent application, wherein the 26. The soft-start circuit according to item 25 of the scope of patent application, wherein the second current mirror is coupled by a first N-type metal-oxide-semiconductor and a second n-type metal-oxide-semiconductor. to make. Page 23 589790 27. The soft-start circuit as described in item 26 of the scope of patent application, wherein the lightness of the N-type metal-oxide-semiconductor field-effect transistor is the input of the first current mirror, and the second N-type metal-oxide-semiconductor field-effect transistor. The drain is the wheel output of the second current mirror. 28. The soft-start circuit according to item 27 in the scope of the patent application, wherein the channel area width-length ratio of the first N-type metal-oxide-semiconductor field-effect transistor is greater than the channel region width of the second N-type metal-oxide-semiconductor field-effect transistor. Longer than. Page 24