Summary of the invention
The embodiment of the present invention is high and cannot meet the requirement problem of more and more higher technique for the cost that solves USB driving circuit.
For solving the problem, the embodiment of the present invention provides a kind of USB driving circuit, and described USB driving circuit comprises:
Control circuit; First driver; And the protection circuit be connected with described control circuit and described first driver respectively; Described control circuit exports according to USB interface signal and controls signal to described protection circuit accordingly; described protection circuit is under the control of described control circuit; protect described first driver; described first driver and USB interface couple, and are suitable for driving USB interface to carry out the data transmission of full speed or low speed.
Alternatively; described protection circuit comprises: the first protection circuit be connected with the first control output end of described control circuit; and the second protection circuit to be connected with the second control output end of described control circuit; one end of described first protection circuit is connected with described second protection circuit; described first protection circuit and described second protection circuit are suitable under the control of described control circuit, protect described first driver.
Alternatively; described control circuit comprises: detecting unit; the comparing unit be connected with described detecting unit; and the control module to be connected with described comparing unit; wherein; described detecting unit is suitable for the magnitude of voltage detecting USB interface signal; described comparing unit is suitable for the magnitude of voltage detected by described detecting unit and first interval of presetting to compare, and described control module is suitable for exporting according to the comparative result of described comparing unit controlling signal to the first protection circuit and the second protection circuit accordingly.
Alternatively, described control module is suitable for, when the magnitude of voltage detected by described detecting unit is in the first interval, exports the first voltage control signal to the first protection circuit, and exporting the second voltage control signal to the second protection circuit.
Alternatively, the span in described first interval is for being more than or equal to 1V, and be less than 4V, the interval of the magnitude of voltage of described first voltage control signal is for being more than or equal to 1.6V, and be less than or equal to 2.0V, the interval of the magnitude of voltage of described second voltage control signal for being more than or equal to 3.0V, and is less than 3.4V.
Alternatively, the span in described first interval, for being more than or equal to 4V, being between the voltage region of described first voltage control signal and described second voltage control signal and being more than or equal to 3.0V, and be less than or equal to 3.4V.
Alternatively, described first protection circuit comprises: the first switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube and the 5th switching tube; The grid of the first switching tube is connected with the grid of second switch pipe, and source electrode is connected with described first driver, and drain electrode is connected with the source electrode of second switch pipe and the source electrode of the 3rd switching tube respectively; The grid of second switch pipe is connected with the first power supply, and drain electrode is connected with the grid of the 3rd switching tube and the drain electrode of drain electrode and the 5th switching tube respectively; The grid of the 4th switching tube is connected with second source, and source electrode is connected with the first power supply, and drain electrode is connected with the source electrode of the 5th switching tube; The grid of the 5th switching tube is connected with the first control output end of described control circuit; The voltage of described first power supply is less than the voltage of second source.
Alternatively, described first switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube and the 5th switching tube are PMOS.
Alternatively, described second protection circuit comprises: the 6th switching tube, the 7th switching tube and the 8th switching tube; The grid of described 6th switching tube is connected with described control circuit second control output end, drain electrode is connected with draining with the grid of described first protection circuit and described 7th switching tube respectively, and source electrode is connected with the source electrode of described 7th switching tube and the drain electrode of the 8th switching tube respectively; The grid of described 8th switching tube is connected with the 3rd power supply, and source electrode is connected with described first driver.
Alternatively, described 6th switching tube, the 7th switching tube and the 8th switching tube are NMOS tube.
Alternatively; described USB driving circuit also comprises: the second driver coupled with described second protection circuit, the first protection circuit and USB interface; described second protection circuit is also suitable under the control of control circuit; protect described second driver, described second driver is suitable for driving USB interface to carry out data at a high speed and transmits.
Alternatively; described USB driving circuit also comprises: the 3rd protection circuit be connected with the 3rd control output end and first driver of described control circuit respectively; described 3rd protection circuit, under the control of described control circuit, protects described first driver and the second driver to be in corresponding duty.
Alternatively, described 3rd protection circuit comprises: the 9th switching tube, and the first end of described 9th switching tube is connected with the 3rd control output end of described control circuit, and the second end is connected with described second protection circuit, and the 3rd end is connected with described first driver.
Alternatively, described 9th switching tube is NMOS tube, and the grid of described NMOS tube is connected with the 3rd control output end of described control circuit, source ground, and drain electrode is connected with described second protection circuit.
Embodiments of the invention additionally provide a kind of USB device, and described USB device comprises above-mentioned USB driving circuit.
Compared with prior art, the technical scheme of the embodiment of the present invention has the following advantages:
Because control circuit exports control signal according to USB interface signal; therefore; when the magnitude of voltage of USB interface signal is larger; described control circuit can export in time and corresponding control signal to protection circuit; described protection circuit under the control of said control signal; protect the first driver not damaged; thus USB driving circuit can be made when not having the device of the voltage arranged can be larger; still larger voltage can be born; and the cost of USB driving circuit can be reduced, and meet the requirement of more and more higher technique.
Embodiment
At present, in order to enable USB driving circuit bear larger voltage, must the device that can bear larger voltage be set in USB driving circuit.Bear the setting of the device of larger voltage, not only make the cost of USB driving circuit increase, and make USB driving circuit cannot meet the requirement of more and more higher technique.
For the problems referred to above; The embodiment provides a kind of USB driving circuit; in described USB driving circuit, the device bearing larger voltage need not be set; and produce corresponding control signal by control circuit according to USB interface signal; protection circuit protects the first driver under the control of said control signal; described USB driving circuit can be made can to bear larger voltage; not only reduce the cost of USB driving circuit, and USB driving circuit can be made can to meet the requirement of more and more higher technique.
For enabling above-mentioned purpose of the present invention, feature and advantage more become apparent, and are described in detail specific embodiments of the invention below in conjunction with accompanying drawing.
See Fig. 1, The embodiment provides a kind of USB driving circuit, described USB driving circuit comprises: control circuit 110, the first driver 120, and protection circuit 130.Wherein, described protection circuit 130 connection control circuit 110 and the first driver 120.Control circuit 110 exports according to USB interface signal and controls signal to protection circuit 130 accordingly, and protection circuit 130, under the control of control circuit 110, protects described first driver 120 not damaged.Described first driver 120 couples with USB interface, is suitable for driving USB interface to carry out the data transmission of full speed or low speed.
In concrete enforcement, USB interface signal can be the input signal of USB system, also can be the output signal of USB system.Because control circuit 110 can produce corresponding control signal according to USB interface signal; therefore; when the magnitude of voltage of USB interface signal is larger; the control signal that protection circuit 130 produces according to control circuit 110; protect the first driver 120 not damaged; that is: the first driver 120 can be made to bear larger voltage, and the device that can bear larger voltage need not be set.
In concrete enforcement, protection circuit 130 can comprise the first protection circuit 1302 and the second protection circuit 1304.Wherein, one end of the first protection circuit 1302 is connected with the second protection circuit 1304, and the first protection circuit 1302 is connected with the first control output end of control circuit 110, and the second protection circuit 1304 is connected with the second control output end of control circuit 110.First protection circuit 1302 and the second protection circuit 1304 are all under the control of control circuit 110; protect the first driver 120, make described first driver 120 in the design not having high resistance to voltage device, still can carry out the data transmission of full speed or low speed in USB interface.
In concrete enforcement, control circuit 110 by first detecting the magnitude of voltage of USB interface signal, then can judge detected magnitude of voltage, and then produces corresponding control signal.Now, control circuit 110 can comprise: the detecting unit 1102 being suitable for the magnitude of voltage detecting USB interface signal, by the comparing unit 1104 that detected magnitude of voltage compares with first interval of presetting, and export the control module 1106 of corresponding control signal according to the comparative result of described comparing unit 1104.
Further; described control module 1106 can produce two control signals; one of them control signal exports the first protection circuit 1302 to through the first output control terminal; another control signal exports the second protection circuit 1304 to through the second output control terminal, controls the first protection circuit 1302 respectively and the second protection circuit 1304 protects described first driver.Such as, control module 1106 can be in the first interval during at the magnitude of voltage detected by detecting unit 1102, the first voltage control signal and the second voltage control signal is exported.Wherein the first voltage control signal can export the first protection circuit 1302 to through the first output control terminal; second voltage control signal can export the second protection circuit 1304 to through the second output control terminal, thus controls the work of the first protection circuit 1302 and the second protection circuit 1304.
In concrete enforcement, the span in described first interval can for being more than or equal to 1V, and be less than 4V, correspondingly, the interval of the magnitude of voltage of described first voltage control signal is for being more than or equal to 1.6V, and being less than or equal to 2.0V, the interval of the magnitude of voltage of described second voltage control signal for being more than or equal to 3.0V, and is less than 3.4V.Such as; control circuit 110 can when the magnitude of voltage of USB interface signal be about 3.3V; send corresponding control signal; make USB driving circuit enter withstand voltage guard mode, described control signal can control the first protection circuit 1302 and the second protection circuit 1304 protects the first driver 120.
In concrete enforcement, the span in described first interval is for being more than or equal to 4V, and correspondingly, the interval of the magnitude of voltage of described first voltage control signal and the second voltage control signal is and is more than or equal to 3.0V, and is less than or equal to 3.4V.Such as, control circuit 110 when the magnitude of voltage of USB interface signal is about 5V, can send corresponding control signal, and make USB driving circuit enter the withstand voltage guard mode of 5V, described control signal can control the first protection circuit 1302.
It should be noted that, in concrete enforcement, described comparing unit 1104 first can determine whether detected magnitude of voltage is more than or equal to 1V, and is less than 4V, when detected magnitude of voltage does not belong to above-mentioned interval, can also determine whether detected magnitude of voltage is more than or equal to 4V again.Or described comparing unit 1104 first can determine whether detected magnitude of voltage is more than or equal to 4V, when detected magnitude of voltage does not belong to above-mentioned interval, can also determine whether detected magnitude of voltage is more than or equal to 1V again, and be less than 4V.As long as detected magnitude of voltage falls in above-mentioned arbitrary interval, control circuit 110 all can produce corresponding control signal according to the description in above-described embodiment.
It should be noted that, the value in described first interval is not limited to above-described embodiment, and those skilled in the art can set according to actual conditions, and the value in described first interval is different, and the magnitude of voltage that described USB driving circuit can bear is also just different.But regardless of the value in the first interval, the first voltage control signal produced as long as corresponding and the second voltage control signal, to control the first protection circuit 1302 and the second protection circuit 1304 protects the first driver 120.
As the above analysis, by setting the value in the first interval, and when making the value of control circuit 110 in the first interval different, the control signal that corresponding generation is different, namely can make USB driving circuit bear different voltage.
In concrete enforcement, described USB driving circuit can also comprise the second driver (not shown).Described second driver is suitable for driving USB interface to carry out data at a high speed and transmits.3rd control output end of described second driver and control circuit 110, one end of the second protection circuit 1304 and USB interface couple, and the second protection circuit 1304, under the control of control circuit 110, protects the second driver not damaged.
In order to strengthen the protection to USB driving circuit further, described protection circuit 130 can also comprise the 3rd protection circuit 1306.Described 3rd protection circuit 1306, under the control of control circuit 110, protects described first driver 120 and the second driver to be in corresponding duty.
Such as, when the magnitude of voltage detected by detecting unit 1102 is greater than 4V, USB driving circuit, under the control of control circuit 110, enters withstand voltage guard mode.Now, control circuit 110, except producing the first voltage control signal and the second voltage control signal, can also produce the 3rd control signal.Described 3rd control signal inputs to the 3rd protection circuit 1306, and described 3rd protection circuit 1306 protects described first driver 120 and the second driver to be in the state of data-transmission interruptions.And when the magnitude of voltage detected by detecting unit 1102 is less than 4V; control circuit 110 still produces the 3rd control signal; described 3rd control signal inputs to the 3rd protection circuit 1306, and described 3rd protection circuit 1306 protects described first driver 120 and the second driver normally to carry out data transmission.
Concrete circuit structure is below adopted to be described in detail to embodiments of the invention:
As shown in Figure 2, in concrete enforcement, the first driver generally includes PMOS M0 and NMOS tube M1.The source electrode of PMOS M0 is connected with second source V2, and grid is connected with power supply FSLS_PU, and drain electrode is connected with the first protection circuit 210.The source ground of NMOS tube M1, grid is connected with power supply FSLS_PD, and drain electrode is connected with the second protection circuit 220.
Detected magnitude of voltage and first interval of presetting by detecting the magnitude of voltage of USB interface signal, and compare by control circuit 230, and then produce different control signal P1, N1 and short.Wherein, control signal P1 exports the first protection circuit 210 to through the first control output end of control circuit 230, works to control the first protection circuit 210.Control signal N1 exports the second protection circuit 220 to through the second control output end of control circuit 230, works to control the second protection circuit 220.Control signal short exports the 3rd protection circuit 240 to through the 3rd control output end of control circuit 230, works to control the 3rd protection circuit 240.
In concrete enforcement, described first protection circuit 210 can comprise the first switching tube M2, second switch pipe M3, the 3rd switching tube M4, the 4th switching tube M5 and the 5th switching tube M6.Wherein, the first switching tube M2, second switch pipe M3, the 3rd switching tube M4, the 4th switching tube M5 and the 5th switching tube M6 can be PMOS, also can be the switching tube of other types, be not construed as limiting herein.In embodiments of the invention, PMOS can be for the first switching tube M2, second switch pipe M3, the 3rd switching tube M4, the 4th switching tube M5 and the 5th switching tube M6 and be described.
As shown in Figure 2, the grid of the first switching tube M2 is all connected the first power supply V1 with the grid of second switch pipe M3, source electrode is connected with the drain electrode of the PMOS M0 of described first driver, and drain electrode is connected with the source electrode of second switch pipe M3 and the source electrode M4 of the 3rd switching tube respectively.The drain electrode of second switch pipe M3 is connected with the grid of the 3rd switching tube M4 and the drain electrode of drain electrode and the 5th switching tube M6 respectively.The grid of the 4th switching tube M5 is connected with second source V2, and source electrode is connected with the first power supply V1, and drain electrode is connected with the source electrode of the 5th switching tube M6.The grid of the 5th switching tube M6 is for control signal P1 input.
Wherein, the voltage of described first power supply V1 is less than the voltage of second source V2.Such as, the voltage of the first power supply V1 can be the voltage of about 1.65V, second source V2 can be about 3.3V.
In concrete enforcement, described second protection circuit comprises 220: the six switching tube M7, the 7th switching tube M8 and the 8th switching tube M9.Wherein, the 6th switching tube M7, the 7th switching tube M8 and the 8th switching tube M9 can be NMOS tube, also can be the switching tube of other types, be not construed as limiting herein.In embodiments of the invention, be NMOS tube for the 6th switching tube M7, the 7th switching tube M8 and the 8th switching tube M9 and be described.
As shown in Figure 2, the grid of described 6th switching tube M7 is for control signal N1 input, drain electrode is connected with draining with the drain electrode of five switching tube M6 and the grid of the 7th switching tube M8 respectively, and source electrode is connected with the source electrode of described 7th switching tube M8 and the drain electrode of the 8th switching tube M9 respectively; The grid of described 8th switching tube M9 is connected with the 3rd power supply V3, and source electrode is connected with the source electrode of the NMOS tube M1 of the first driver.Wherein, the voltage of the 3rd power supply V3 can be about 1.8V.
In concrete enforcement, described USB driving circuit can also comprise and is suitable for driving USB interface to carry out the second driver of data transmission at a high speed.Described second driver can comprise NMOS tube M10 and NMOS tube M11.Wherein, the drain electrode of NMOS tube M10 is with the source electrode of the 8th switching tube M9 and the drain electrode of NMOS tube M11 is connected, grid is connected with power supply HS_PD, source ground.The grid of NMOS tube M11 is connected with power supply HS_PU, and source electrode is connected with the power supply of 0.8V.
In concrete enforcement, described 3rd protection circuit 240 can comprise the 9th switching tube M12.The first end of the 9th switching tube M12 is connected with the 3rd control output end of control circuit, and for control signal short input, the second end is connected with the source electrode of the 8th switching tube M9, the 3rd end ground connection.All can be described for NMOS tube for described 9th switching tube M12 below, now, the grid of NMOS tube is first end, and drain electrode is the second end, and source electrode is the 3rd end.
When the magnitude of voltage of USB interface signal is more than or equal to 1V; and when being less than 4V; the magnitude of voltage of the control signal short that control circuit 230 produces is that the 0, nine switching tube M12 ends, and the first protection circuit 210 and the second protection circuit 220 protect the first driver to carry out normal data transmission.Now, the magnitude of voltage of the control signal P1 that control circuit 230 produces simultaneously can for being more than or equal to 1.6V, and be less than or equal to arbitrary magnitude of voltage of 2.0V, and the magnitude of voltage of control signal N1 can for being more than or equal to 3.0V, and be less than or equal to arbitrary magnitude of voltage of 3.4V, such as, the magnitude of voltage of described control signal P1 is 1.8V, and the magnitude of voltage of described control signal N1 is 3.3V.
When control signal P1 inputs to the 5th switching tube M6 of the first protection circuit 210, the voltage between the grid of the 5th switching tube M6 and drain electrode is less than voltage breakdown (being approximately 2V), and then makes the 5th switching tube M6 can not be damaged.Meanwhile, the drain voltage of the 4th switching tube M5 is suitably raised, and the voltage between the grid of the 4th switching tube M5 and drain electrode is less than voltage breakdown, and then makes the 4th switching tube M5 can not be damaged.Similarly, because the existence of the voltage of the first power supply V1, the voltage between the grid of the 3rd switching tube M4, second switch pipe M3 and the first switching tube M2 and drain electrode is made also all to be less than voltage breakdown.Further, the voltage between PMOS M0 drain electrode and grid is also less than voltage breakdown.That is, the input of control signal P1, makes the PMOS M0 of the first protection circuit 210 and the first driver not damaged.
When control signal N1 inputs to the 6th switching tube M7 of the second protection circuit 220; based on same principle, the voltage between the drain electrode of the NMOS tube M1 of the 6th switching tube M7, the 7th switching tube M8, the 8th switching tube M9 and the first driver and grid is also all less than voltage breakdown.Like this, the input of control signal N1, makes the NMOS tube M1 of the second protection circuit and the first driver not damaged.
When the magnitude of voltage of USB interface signal is more than or equal to 4V, the magnitude of voltage of the control signal short that control circuit 230 produces is the 1, nine switching tube M12 conducting, and the first driver interrupts the transmission of data, and whole driving circuit enters withstand voltage guard mode.Now, the magnitude of voltage of the control signal P1 that control circuit 230 produces simultaneously and N1 can be and be more than or equal to 3.0V, and is less than or equal to arbitrary magnitude of voltage of 3.4V, and such as, the magnitude of voltage of described control signal P1 and N1 is 3.3V.When control signal P1 and N1 inputs to the first protection circuit 210 and the second protection circuit 220 respectively, those skilled in the art with reference to above-mentioned principle, can understand the control action of control signal P1 and N1, repeat no more herein.
Known by above-mentioned analysis, under the control signal P1 of control circuit 230 output and the control of N1, the first protection circuit 210 and the second protection circuit 220 can play a protective role to whole driving circuit.
Embodiments of the invention additionally provide a kind of USB device.Described USB device can comprise above-mentioned USB driving circuit, drives USB interface to carry out full speed, low speed or the transmission of data at a high speed by USB driving circuit.
Although the present invention discloses as above, the present invention is not defined in this.Any those skilled in the art, without departing from the spirit and scope of the present invention, all can make various changes or modifications, and therefore protection scope of the present invention should be as the criterion with claim limited range.