Over-temperature protection with soft turn-off for power amplifiers

Abstract

Various methods and circuit arrangements for protecting a power amplifier (110) from over-temperature are presented. According to one aspect, a protection circuit coupled to a temperature sensor (338) controls a bias current or voltage to a power amplifier (110) to limit power dissipation through the power amplifier (110) when sensing a high limit temperature, and thus a temperature of the power amplifier (110). Upon sensing a high limit temperature, the bias current or voltage is reduced according to a linear function of the sensed temperature while allowing the power amplifier (110) to operate. The slope of the linear function and the value of the high-limit temperature may be programmable. The programmability of high limit temperature and slope may be used to control bias current or voltage to a plurality of power amplifiers (112, 113) that operate at different times and have different thermal requirements.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 17 / 821,731, filed on August 23, 2022, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present application relates to amplifiers. In particular, the present application relates to over-temperature protection of a power amplifier (PA). Background Art

[0004] Figure 1 A prior art radio frequency (RF) power amplifier (PA) module (110) is shown, which may be used, for example, in a transmitter portion of an RF front-end communication system such as, for example, a mobile communication system. Figure 1 As shown in the configuration (100A), the power amplifier module (110) may include a plurality of cascaded amplifier stages (e.g., 112, 113), which are coupled in series via matching networks (e.g., MN1, MN2, MN3) for amplifying an input RF signal RFin, thereby generating an amplified output RF signal RFout based on the amplified input RF signal RFin. Power to the amplifier stages (112, 113) is provided via a supply voltage Vcc referenced to a reference ground Vgnd, which is coupled to the amplifier stages (112, 113) via corresponding inductors (L2, L3). The amplified signal RFout can in turn be coupled to an antenna of the PA module (e.g., described later according to the invention) via, for example, an antenna switch. Figure 7 elements 740 and 750) for transmission.

[0005] like Figure 1 As shown in , the input stage of each of the amplifier stages (112, 113) may include a corresponding common emitter transistor (Tr12, Tr13), the base of which receives an input RF signal, which is amplified by the common emitter transistor (Tr21, Tr13) and output at the corresponding collector of the transistor (e.g., detail in the lower right corner of the figure), which is coupled to the supply voltage Vcc through the corresponding inductor (L2, L3), and coupled to the corresponding output of the amplifier stage (112, 113). Through each of the amplifier stages (112, 113), and therefore through the amplification of the PA module (110), the operating point (i.e., bias point) of the common emitter transistor (Tr12, Tr13) can be established based on the bias of the amplifier stage (112, 113). As shown in Figure 1As can be seen in Figure 1A, such biasing is provided via a bias circuit (120) comprising emitter follower transistors (Tr22, Tr23) coupled to respective inputs of amplifier stages (112, 113). The emitter of each of the emitter follower transistors (Tr22, Tr23) is coupled to the base of a respective common emitter transistor (Tr21, Tr23) via a series connected resistor (R12, R13), which is known in the art as a "ballast" resistor. Thus, the bias circuit (120) provides a bias signal to each of the amplifier stages (112, 113), which bias signal can be considered as a bias voltage or a bias current.

[0006] Continue to refer to Figure 1 The bias circuit (120) may generate a bias signal under the control of a controller circuit (130), which may include a control / interface circuit (132) for receiving commands from, for example, a signal sensing processor (such as, for example, a transceiver circuit) and converting such commands into control signals for generating corresponding bias signals for biasing the PA module (110). Figure 1 In the exemplary prior art case shown, a digital-to-analog (DAC) converter (135) is used to generate a control signal (i.e., a current or voltage) to the emitter follower transistors (Tr22, Tr23) of the bias circuit (120). Figure 1 As shown, the DAC converter (135) can provide a voltage to the base of each of the emitter follower transistors (Tr22, Tr23) so that a desired bias signal can be output at the emitter of each such transistor for biasing the PA module (110). The series-connected diode pairs (D21, D22) and (D31, D32) coupled between the reference ground Vgnd and the base of the corresponding emitter follower transistors (Tr22, Tr23) can be used to offset thermal variations of the common emitter transistors (Tr12, Tr13) and in some cases prevent thermal runaway of the common emitter transistors (Tr12, Tr13) as known in the art.

[0007] like Figure 2 As shown in the graph of FIG. 1 , the temperature (PAtemp) of the PA module (110) can be a function of its output power (P OUT ), but may also be a function of external parameters (EP), such as, for example, ambient temperature or others (e.g., transceiver operation), which in turn may affect other parameters that may also be considered external parameters of the PA module (110), such as the level of the supply voltage Vcc, the input RF signal RFin, input / output matching conditions, etc. Figure 2 As shown in FIG. , when the first output power P OUT1When in operation, the temperature PA temp may be an increasing function of (one or more levels of) the external parameter EP, but may not reach the breakdown temperature T of the PA module (110). BD On the other hand, when the output power is higher than the first output power P OUT1 The second output power P OUT2 When operating, the temperature PAtemp may be an increasing function of (one or more levels of) an external parameter EP, while Figure 2 EP BD The breakdown temperature T of the PA module (110) is reached at the external parameter level / value indicated BD In other words, for some output power ranges of operation of the PA module (110), changes in the level of the external parameter may cause the PA module (110) to break down due to an over-temperature condition.

[0008] Some prior art solutions for over-temperature protection of power amplifiers (PAs) may be based on hard shut-down of the PA that inhibits PA operation. Although such prior art hard shut-down schemes may be effective in protecting the amplifier module from breakdown due to over-temperature, such schemes may also force interruption of any activity related to the operation of the amplifier module (e.g., transmission of RF signals). It can be seen that it may be necessary to shut down an RF amplifier module (e.g., Figure 1 Improved over-temperature protection of an RF power amplifier module (110) shown in the prior art configuration of the present invention not only protects the amplifier from thermal breakdown due to over-temperature, but also maintains the ongoing activity of the amplifier (e.g., soft shutdown). Such improved over-temperature protection is provided according to the teachings of the present disclosure. Summary of the invention

[0009] According to a first aspect of the present disclosure, a circuit is proposed, which includes: a bias circuit, which is configured to supply a bias signal based on a control current; and a protection circuit, which is configured to detect a temperature and generate a control current based on the detected temperature, wherein, for: i) a detected temperature below a preset high temperature limit, the control current is constant, and ii) a detected temperature above the preset high temperature limit, the control current is a linear function of the detected temperature, and the linear function has a negative slope with respect to an increasing value of the detected temperature.

[0010] According to a second aspect of the present disclosure, a method for controlling current through an amplifier is proposed, the method comprising: based on a detection value of the temperature of the amplifier, controlling the current to the amplifier so that for a detection value of the temperature above a preset temperature limit, the current to the amplifier decreases linearly with respect to the increasing temperature detection value, and based on the control, for a detection value of the temperature above the preset temperature limit, reducing the power dissipated through the amplifier.

[0011] Further aspects of the disclosure are provided in the description, drawings and claims of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the present disclosure and, together with the description of the example embodiments, serve to explain the principles and implementations of the present disclosure.

[0013] Figure 1 A prior art RF power amplifier (PA) module and a bias circuit for providing a bias signal to the PA module are shown.

[0014] Figure 2 The figure shows the variation level of the external parameters of the PA module for a given output power of the PA module. Figure 1 A graph of the temperature variation of the PA module.

[0015] Figure 3A Configurations of an RF power amplifier (PA) module and a bias circuit that provides a bias signal to the PA module are shown, wherein the bias circuit reduces current through the PA module for increasing values ​​of the temperature of the PA module in accordance with an embodiment of the present disclosure.

[0016] Figure 3B The figure shows the variation level of the external parameters of the PA module for a given output power of the PA. Figure 3A A graph of the temperature of the PA module.

[0017] Figure 4A A simplified schematic diagram of an over-temperature protection circuit according to an embodiment of the present disclosure is shown.

[0018] Figure 4B and Figure 4C Shown as Figure 3A The variation of the PA module as a function of temperature is given by Figure 4A A graph showing the current manipulation performed by the overtemperature protection circuit.

[0019] Figure 5A It shows that it can be Figure 4A A simplified schematic diagram of the voltage to current converter circuit used in the overtemperature protection circuit shown in FIG.

[0020] Figure 5B Shows Figure 5A Schematic diagram of a voltage-to-current converter circuit for generating a constant current for use Figure 4A The over temperature protection circuit shown in .

[0021] Figure 5CShows Figure 5A A schematic diagram of a voltage-to-current converter circuit for generating a varying current based on a varying voltage sensed by a temperature sensor for use in Figure 4A The over temperature protection circuit shown in .

[0022] Fig. 6A A simplified schematic diagram of another over-temperature protection circuit according to an embodiment of the present disclosure is shown.

[0023] Figure 6B and Figure 6C Shown as Figure 3A The variation of the PA module as a function of temperature is given by Fig. 6A A graph showing the current manipulation performed by the overtemperature protection circuit.

[0024] Figure 7 A simplified block diagram of the transmitter portion of an RF front-end communication system using multiple PA modules is shown. Figure 3A The configuration shown in and shared according to Figure 4A or Fig. 6A A single over-temperature voltage protection circuit configured.

[0025] Fig. 8A A simplified schematic diagram of another over-temperature protection circuit according to an embodiment of the present disclosure is shown.

[0026] Figure 8B Shown Fig. 8A A graph of the operation of the over temperature protection circuit.

[0027] Fig.9A Shown based on Figure 3A A variation of the configuration shown in , a configuration according to an embodiment of the present disclosure.

[0028] Fig. 9B Shown based on Figure 3A Another variation of the configuration shown in , a configuration according to an embodiment of the present disclosure.

[0029] Fig. 9C An RF power amplifier comprising a FET transistor stack is shown.

[0030] Fig.10 is a process diagram illustrating various steps of a method for controlling current through an amplifier according to an embodiment of the present disclosure.

[0031] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION

[0032] Throughout this disclosure, embodiments and variations are described for the purpose of illustrating the uses and implementations of the inventive concepts of various embodiments. The illustrative descriptions should be understood to present examples of the inventive concepts rather than to limit the scope of the concepts disclosed herein.

[0033] Figure 3A A configuration (300A) according to an embodiment of the present disclosure is shown, which includes an RF power amplifier (PA) module (110) and a bias circuit (120) that provides a bias signal to the PA module (110), wherein, under the control of a controller circuit (330), the bias circuit (120) can be configured to reduce the collector current (e.g., Icc2 and / or Icc3) through the PA module (110) for an increased value of the (sensed) temperature of the PA module (110) exceeding a high temperature limit, thereby preventing an over-temperature breakdown of the PA module (110) without shutting down (the operation of) the PA module (110). In other words, the current (value) through the collector of one or more of the common-emitter transistors (Tr12, Tr13) of the PA module (110) can: for a temperature value of the PA module (110) below the high temperature limit, be unchanged (e.g., constant); and for a temperature value of the PA module (110) above the high temperature limit, be reduced. Such a reduction in collector current (e.g., Icc2 and / or Icc3) can correspondingly reduce the power dissipation of the PA module (110) and thus reduce the temperature of the PA module (110) while allowing the PA module (110) to continue to operate. As a result of the reduction in power dissipation of the PA module (110), and as Figure 3B As shown in the above reference, Figure 1 to Figure 2 The effect of the external parameter (EP) on the temperature of the PA module (110) is described. It should be noted that although the bias circuit (120) can be described as a circuit separate from the PA module (110) mainly based on the separate functions of the bias circuit (120) compared to the PA module (110), in some embodiments, the PA module (110) can be described as also including the bias circuit (120), or even including the controller circuit (330). Therefore, such a combination of circuits can be monolithically integrated into a single chip.

[0034] Figure 3B The figure shows the change level of the external parameter EP based on the PA module (110). Figure 3A A graph of the temperature (for a given output power) of a PA module (110). Figure 3B As shown in FIG. 1 , for the change level of the external parameter EP, when the temperature PA temp of the PA module (110) is lower than the high temperature limit T LWhen the temperature PAtemp of the PA module (110) is higher than the high temperature limit T L When the PA temperature PA temp is increased, PA temp may increase at a lower rate (smaller slope). The lower rate of increase of the PA temperature PA temp may be attributed to the decrease in the collector current (e.g., Icc2 and / or Icc3) described above, which may be, for example, a linear decrease with increasing values ​​of the PA temperature above the high temperature limit. It should be noted that although Figure 3B The curve graph is in coordinates (EP BD , T L ) shows the inflection point of the curve (PAtemp with respect to EP), but according to the teachings of the present disclosure, EP may not be required. BD Prior knowledge of the value or by EP BD denoted by a specific external parameter. In contrast, according to the teachings of the present disclosure, the global impact of the external parameter observed by the sensed PA temperature (PAtemp) can be measured and the bias of the PA module (110) controlled accordingly. In other words, for the overtemperature protection scheme according to the present disclosure, a sufficient input can be the sensed temperature. Although the sensed temperature can be the local temperature of the PA module (110), in some embodiments according to the present disclosure, other temperatures can also be used, such as the ambient temperature (e.g., room temperature) of the device (e.g., a cellular phone) including the PA module (110). For example, the ambient temperature can be used in the case where the impact of the external parameter can be primarily attributed to the ambient temperature.

[0035] According to the teachings of the present disclosure, the bias signal to the PA module (110) can be controlled to offset / reduce / mitigate the effect of the external parameter EP on increasing the temperature of the PA module (110) while allowing the operation of the PA module (110) to continue. As described above, such control of the bias signal can be, for example, for a temperature above a high temperature limit T L The sensed PA temperature, the collector current (e.g., Figure 3A Icc2 and / or Icc3) is linearly reduced to obtain Figure 3B The linear reduction is based on a decreasing linear function of the (collector) current for temperatures above the high temperature limit T L The value of the increase in the sensed PA temperature (eg, as described later) Figure 4B According to another exemplary embodiment of the present disclosure, the decreasing linear function may be segmented based on the value of the sensed PA temperature, wherein the linear segments have different slopes (e.g., negative slopes) with respect to increasing values ​​of the sensed PA temperature.

[0036] Return to reference Figure 3A According to an embodiment of the present disclosure, the temperature of the PA module (110) can be sensed by a temperature sensor TS (338) that can be placed in the vicinity of the PA module (110). According to an exemplary embodiment of the present disclosure, the temperature sensor (338) can be placed closer to a higher output power (e.g., hotter, higher temperature) stage of the PA module (110), such as, for example, closer to Figure 3A 113. According to a non-limiting embodiment of the present disclosure, the temperature sensor (338) may be embedded / fabricated within the same die used to manufacture the PA module (110) or a stage thereof (e.g., 113). Such close proximity of the temperature sensor (338) to the PA module (110) may allow sensing of a local temperature of the PA module (110), which may therefore be indicative of the temperature of the PA module (110). According to an exemplary embodiment of the present disclosure, the temperature sensor (338) may be a diode to which a bias current (e.g., as described later) may be provided. Figure 5C ). The temperature sensor (338) according to the present teachings may be any temperature sensor known in the art, including, for example, a thermocouple, a resistor, or other temperature sensor that may be suitable for integration with the PA module (110) or otherwise sensing a local temperature or ambient temperature. In addition, as described later in the present disclosure, a characteristic response curve for such a temperature sensor may be provided by an output voltage that decreases with respect to an increasing sensed temperature, or by an output voltage that increases with respect to an increasing sensed temperature. Implementations of over-temperature protection schemes according to the present disclosure for each of such characteristic responses of a temperature sensor are described later in the present disclosure (e.g., with reference to Figure 4A and Fig. 6A ).

[0037] Also refer to Figure 3A According to an embodiment of the present disclosure, the voltage V output by the temperature sensor TS (338) TPA can be provided as an input to the controller circuit (330) and based on the voltage V TPA , the controller circuit (330) can generate a current I that can be supplied to the collector of the emitter follower transistor (Tr22, Tr23) of the bias circuit (120) OUT_OTP Current I OUT_OTP The (high) value of the bias current (Ib2, Ib3) to the common emitter transistor (Tr12, Tr13) can be limited, which in turn limits the (high) value of the collector current (Ic2, Ic3). Figure 3A As seen in FIG. 1 , the voltage V output by the temperature sensor (338) TPAcan be provided as an input to a current control circuit (335) which controls the current generator circuit (235) to output a current I OUT_OTP As described later Figure 4C As shown in OUT_OTP It may be constant for the lower temperature range of the PA and may include a (negative) slope for the higher temperature range of the PA. According to another embodiment of the present disclosure, the current control circuit (335) may also control / generate the current I OUT_OTP In other words, such a slope may be programmable. According to another embodiment of the present disclosure, the current control circuit (335) may determine the voltage V at which the slope starts. TPA In other words, the inflection point of the slope (e.g. Figure 3B ) can be programmable. Via a temperature sensor (e.g., Figure 3A The programmability of the value of the slope and the starting position of the TS 338) in combination with the current control circuit (335) can allow the current generator circuit (235) to be used to control the bias current to multiple different PA module parts, such as those described later. Figure 7 Multiple different PA module portions of the same transmitter portion of the RF front-end communication system shown in .

[0038] Figure 4A The embodiment according to the present disclosure can be used to provide over-temperature protection. Figure 3A A simplified schematic diagram (400A) of the components (235, 335, 338) of the controller circuit (330), which may be referred to as a temperature protection circuit, is shown in FIG. Figure 4A As shown in FIG. , the temperature sensor circuit (338) can sense / detect a temperature (eg, a local temperature or an ambient temperature) and generate a corresponding control signal V according to the sensed temperature / detected temperature. TPA , to control the current I output by the current source (3352) of the current control circuit (335) TPA According to an embodiment of the present disclosure, the current I TPA The size of the control signal V TPA is proportional to the level of, and therefore proportional to the level of the temperature sensed by the temperature sensor circuit (338). In other words, within the voltage range of interest, I TPA = k*V TPA The factor k may be programmable and provided, for example, by varying the number of parallel current sources (current mirrors) of the current source (3352) by design and methods well known to those skilled in the art, the details of which are beyond the scope of this disclosure. It should be noted that Figure 4AThe configuration shown in the figure is customized to have Figure 3B The temperature sensor circuit (338) has a non-limiting characteristic response curve and thus has a reduced sensed voltage / output voltage for increasing temperature.

[0039] Continue to refer to Figure 4A , generating a constant current I CON The current source (3351) is connected in series with two separate current paths, one path including the current source (3352) and the other path including the reference branch of the current mirror (3353). As is clearly understood by those skilled in the art, as long as the current I TPA Greater than the current I generated by the current source (3351) CON , then the entire current I CON flows through the current source (3352), and therefore no current flows through the reference branch of the current mirror (3353). In other words, the current I' through the reference branch SINK and the corresponding current I of the target branch through the current mirror (3353) SINK On the other hand, when the current I TPA is less than the current I generated by the current source (3351) CON When the residual (difference) current I is higher than the current that the current source (3352) can absorb CON -I TPA flows through the reference branch of the current mirror (3353), and thus the corresponding current I SINK =K*I' sink =K*(I CON -I TPA ) flows through the target branch of the current mirror (3353), where K is a number corresponding to the ratio of the current between the reference branch and the target branch of the current mirror (3353).

[0040] According to the above description, the current I of the target branch through the current mirror (3353) SINK For: i) TPA ≥I CON The voltage V output by the temperature sensor (338) TPA , equal to zero, and ii) for I TPA CON The voltage V output by the temperature sensor (338) TPA The value is equal to K*(I CON -I TPA ). Since the current I TPA With voltage V TPA is proportional to the value of SINK When it is non-zero, it increases with the voltage V TPA ​In other words, when the current I SINK When it is non-zero, it increases in proportion to the increasing temperature value sensed by the temperature sensor (338). In addition, the current I SINK Regarding the reduced voltage V TPA The rate of increase or slope of the value of I is based on the number K. In other words, by programmatically changing the value of K, the current I SINK The slope of (when not zero) can be changed. Those skilled in the art are well aware of the design techniques for providing a parameterized (programmable) ratio K of the current mirror (e.g., 3353). Finally, by programmatically changing the current I generated by the current mirror (3351), CON The magnitude of the current I' SINK The start-up current I flows through the reference branch and thus SINK The activation of the target branch flowing through the current mirror (3353) can be used as the voltage V TPA The value of (or in other words, the value of temperature) changes as a linear function. For example, for the current I CON Higher values ​​of V may be required TPA A proportionally higher value of, and therefore a proportionally lower value of the temperature sensed by the temperature sensor (338) may be required to initiate current flow through the current mirror (3353).

[0041] Therefore, the programmability of the current source (3351) and the programmability of the ratio K of the current mirror (3353) can provide currents I SINK The position and magnitude of the slope (as described later) Figure 4B According to an exemplary embodiment of the present disclosure, Figure 4A As shown in FIG. 1 , the current source (3351) and the current mirror (3353) can be programmed by generating corresponding control signals (CTL 3351 , CTL 3353 ) is provided by a control circuit (3354) of the current control circuit (335). According to an alternative embodiment, the control circuit (3354) may be external to the current control circuit (335), such as, for example, may be part of a signal sensing controller (such as a transceiver system). It should be noted that control of various controllable and / or programmable elements / circuits according to the present teachings may require control lines and signals, which may not be shown in the current figures, but are undoubtedly well understood by those skilled in the art.

[0042] Continue to refer to Figure 4A , the current generator circuit (235) may include generating a reference current I REF The reference current generating circuit (2351) generates a reference current from the reference current I REF The current I generated by the current control circuit (335) is subtracted fromSINK To generate Figure 4A The current (I REF -I SINK ), the current (I REF -I SINK ) is fed to the output stage (2352), which can multiply such current to generate a larger current I OUT_OTP , the larger current I OUT_OTP Provided to Figure 3A The bias circuit (120) shown in FIG. SINK The voltage V is equal to zero TPA The value of current I OUT_OTP It can be a reference current I REF Determine the fixed / constant current, and for making I SINK The voltage V is not equal to zero TPA The value of current I OUT_OTP It can be a reference current I REF Subtract the voltage V as described above TPA A linear function of the current I SINK It should be noted that the reference current generating circuit (2351) can be programmable to output reference currents I of different magnitudes. REF and can be made independent of temperature variations (at least within the temperature range of interest) via embedded temperature compensation circuits / elements as are known in the art.

[0043] Figure 4B and Figure 4C Shown with reference to above Figure 4A The generation / manipulation of various currents described corresponds to the following graphs. In particular, Figure 4B The graph (a) shows the constant current I CON and (temperature) current I TPA At the temperature limit point T L As mentioned above, the constant current I CON The programmable value of combined with the known characteristic response curve of the temperature sensor (338) allows the intersection point to be mapped to the desired temperature limit point T L Based on such intersections, Figure 4B As shown in the graph (b) of Figure 3A The current I' of the reference branch of 3353) SINK , which in turn Figure 4B As shown in the curve diagram (c), it can be established that the current I OUT_OTP The current difference I REF -–I SINK Based on the current difference I REF -ISINK For current I OUT_OTP Established in Figure 4C As shown in the graph, including establishing a) reference current I REF , and b) current I SINK , the current I SINK For temperatures below the limit point T L The temperature value has a zero value, and the current I SINK For temperatures above the limit point T L The temperature value of has a positive non-zero value with a positive slope.

[0044] Figure 5A An exemplary embodiment according to the present disclosure is shown which can be used to implement the above reference Figure 4A A simplified schematic diagram of a voltage-to-current converter circuit (500A) with over-temperature protection is described. Figure 5A As shown in FIG. , an operational amplifier (515) connected in a non-inverting configuration receives an input voltage V at its non-inverting input terminal (denoted by a + symbol in the drawing). IN Therefore, the voltage at the inverting input terminal (denoted by the symbol - in the figure) of the operational amplifier (515) is V IN , then the voltage V IN is provided to a shunt resistor R55 coupled between the inverting input terminal of the operational amplifier (515) and the reference ground Vgnd. Figure 5A As shown in , a PMOS current mirror (525) - comprising a first PMOS transistor (525a) portion of a reference branch of the PMOS current mirror (525) and a second PMOS transistor (525b) portion of a target branch of the PMOS current mirror (525) - is coupled to an operational amplifier (515) such that the gates of the first and second PMOS transistors (525a, 525b) are connected / coupled to the output of the operational amplifier (515), and the drain of the first PMOS transistor (525a) is coupled to a common node coupling the inverting input of the operational amplifier (515) with a shunt resistor R55. In addition, the sources of the first and second PMOS transistors (525a, 525b) are coupled to a (substantially) fixed supply voltage Vdd. Such a fixed supply voltage Vdd may be based on a regulated voltage of, for example, a battery. In some non-limiting exemplary embodiments, the fixed supply voltage Vdd may be approximately 3 volts, while the supply voltage Vcc (eg, shown in other figures) may vary from approximately 3 volts up to approximately 6.5 volts or more.

[0045] Continue to refer to Figure 5A , because the voltage at the drain of the first transistor (525a) is equal to the input voltage V IN, so the current I' through the shunt resistor R55 and thus through the reference branch of the PMOS current mirror (525) (ie, through 525a) VIN Equal to V IN / R55, and the current I' VIN Therefore, with the input voltage V IN Therefore, the current I flowing through the target branch of the PMOS current mirror (525) (i.e., through 525b) is VIN ——The current I VIN is the current I' flowing through the reference branch VIN A scaled version of the input voltage V IN Therefore, Figure 5A The circuit shown in the figure can be used to generate a IN Proportional source current I VIN In addition, if Figure 5A As shown in FIG. 1 , an NMOS current mirror (526) including a first NMOS transistor (526a) portion of a reference branch of the NMOS current mirror (526) and a second NMOS transistor (526b) portion of a target branch of the NMOS current mirror (526) can be coupled to a PMOS current mirror (525) to generate a current that is also related to the input voltage V IN Proportional to the sink current I” VIN .

[0046] Continue to refer to Figure 5A According to an exemplary embodiment of the present disclosure, the shunt resistor R55 may optionally have a programmable, variable, settable resistance that can be controlled / changed in steps and / or continuously. Such programmability of the resistor R55 may allow for the Figure 5A The resistor R55 in the circuit shown in FIG. 1 provides for calibration of the voltage and current response. Such programmability can be used to overcome the difficulties in manufacturing Figure 5A The circuit shown in FIG. 1 is a circuit that is calibrated to reduce the resistance variation of the circuit in the manufacturing process (e.g., CMOS process). Such calibration via adjustment of the resistance value of resistor R55 can be performed at Figure 5A The circuits shown in the drawings may be integrated at any stage of the process, including at the factory prior to shipment and / or at the assembly site where, for example, the circuits may be integrated with the Figure 3A The circuit shown in the Figure 5A The circuit is assembled as a part of a transmitter device (such as, for example, a portable mobile device / handheld mobile device).

[0047] Figure 5A The current converter circuit (500A) can be used to generate, for example, Figure 4A The constant current I CONand / or current I TPA . This is respectively Figure 5B and Figure 5C In Figure 5B In the configuration (500B), the input voltage to the current converter circuit is a constant voltage V CON , based on the constant voltage V CON Generated current I CON Therefore, the constant voltage V CON Different values ​​of and / or different ratios of the transistors (525a, 525b) of the PMOS mirror (525) can provide a current I CON On the other hand, in Figure 5C In the configuration (500C), the input voltage to the current converter circuit is the voltage V output by the temperature sensor (e.g., 538). TPA , the voltage V TPA Generated current I TPA . Because in Figure 4A In the configuration shown in TPA is the sink current, so then as in Figure 5C As shown in FIG. 5 , the NMOS current mirror (526) can be used to generate a sink current I based on the source current output by the PMOS current mirror (525). TPA .

[0048] Continue to refer to Figure 5C According to an exemplary embodiment of the present disclosure, the temperature sensor (538) may be based on a (constant / fixed) bias current I TS Output voltage V TPA According to an exemplary embodiment of the present disclosure, the diode D can be controlled by the control signal En through its on / off state. TS The controlled (PMOS) transistor switch (539) provides a bias current I TS According to an exemplary embodiment of the present disclosure, the control signal En TS You can refer to the above Figure 4A The control circuit (3354) described herein provides. In some cases, the control signal En TS Can be used to generate a constant current I CON of Figure 5B It should be noted that the teachings of the present disclosure may not be limited to being located in close proximity to a PA module (e.g., Figure 3A 100) for measuring / sensing an indication PA module (e.g., Figure 3A The temperature of the local temperature of the temperature sensor (e.g., 538) of 100). Therefore, Figure 5A The temperature sensor (538) can be located in the PA module (e.g., Figure 3A 100) local or remote from the PA module.

[0049] Fig. 6A Another embodiment of the present disclosure can be used to provide over-temperature protection. Figure 3A 600A is a simplified schematic diagram (600A) of the elements (235, 335, 338), which may be referred to as a temperature protection circuit, of the controller circuit (330) shown in FIG. Fig. 6A The configuration shown in can be used with Figure 3B The above curves shown in the temperature sensor circuit (338) are used together with different characteristic response curves. In particular, Fig. 6A The configuration shown in can be used with a temperature sensor (338) having a characteristic response curve with an increasing sensed voltage / output voltage for increasing temperature. In other words, Fig. 6A The current control circuit (335) can be considered as the above reference Figure 4A The dual of the current control circuit (335) described above. Fig. 6A The target branch current I of the current mirror (3353) SINK Yes: i) For I CON ≥I TPA The voltage V output by the temperature sensor (338) TPA , equal to zero, and ii) for I CON TPA The voltage V output by the temperature sensor (338) TPA The value is equal to K*(I TPA -I CON ). Since the current I TPA With voltage V TPA is proportional to the value of SINK When it is non-zero, it increases with the voltage V TPA In other words, when the current I SINK When non-zero, it increases proportionally with increasing temperature values ​​sensed by the temperature sensor (338). Figure 6B and Figure 6C The corresponding current curves are shown in Figure 4B and Figure 4C The curve graph provides a relevant description.

[0050] Figure 7 A simplified block diagram (700) of a transmitter portion of an RF front-end communication system using a plurality of PA modules (110a, 110b, ..., 110k) is shown, each PA module being configured according to Figure 3A ​The configuration shown in is coupled to a corresponding bias circuit (120a, 120b, ..., 120k) and includes a circuit for Figure 4A or Fig. 6A The above description provides a (shared) element (235, 335, 338) for over-temperature protection for each of the PA modules. Figure 4A and Fig. 6A described above, and FIG. 4B to FIG. 4C and FIG. 6B to FIG. 6C Other views of the curves described are obtained by combining a temperature sensor (338) and a current control circuit (335). Figure 7 The current I output by the current generator circuit (235) shown in OUT_OTP The slope value (about V TPA The rate of change of the change) and the starting position of the slope (i.e., based on the temperature limit point T L ) programmability allows the current generator circuit (235) to be used to control bias current to multiple different PA modules (110a, 110b, ..., 110k) portions of the same transmitter portion of, for example, an RF front-end communication system.

[0051] Continue to refer to Figure 7 At any given time, one of the plurality of PA modules (110a, 110b, ..., 110k) can be coupled to the antenna (750) via the antenna switch (740) for transmitting the amplified RF signal (RFout_a, RFout_b, ..., RFout_k). Therefore, based on the above reference, for example Figure 3A In view of the PA module (e.g., 110b) selected to be coupled to the antenna (750), the DAC converter (135) can control the base voltage of the emitter follower transistor (e.g., Tr22, Tr23) of the corresponding bias circuit (120b) so that a desired bias signal can be output at the emitter of each such emitter follower transistor for biasing the PA module (110b). At the same time, the current I can be adjusted based on, for example, the thermal characteristics (e.g., including the thermal breakdown temperature) of the selected PA module (110b). OUT_OTP The slope and position of the slope can be programmed. Figure 7 As shown in FIG. 1 , the temperature sensor (338) can be arranged at any suitable location for sensing the temperature of any one of the plurality of PA modules (110a, 110b, ..., 110k). In some cases, the temperature sensor (338) can be placed (e.g., away from the PA module) to sense the temperature environment within which the RF front-end communication system (in Figure 7 700).

[0052] Fig. 8A Another embodiment of the present disclosure is shown which can be used to provide over-temperature protection. Figure 3A 800A) of the components (235, 335, 338) of the controller circuit (330), which may be referred to as a temperature protection circuit. In particular, although Fig. 8A The elements (235, 338) shown in FIG. 2 can be compared with those shown in FIG. Figure 4A or Fig. 6A The elements (235, 338) described are the same, but Fig. 8A The element (335) is different. Fig. 8A As shown in SINK can be generated by a current source (8351) under the control of an (error) amplifier Amp. According to an embodiment of the present disclosure, the amplifier Amp can output a control voltage A OUT , the control voltage A OUT It can be the voltage V supplied to the non-inverting input terminal of the amplifier Amp. TPA The reference limit voltage V supplied to the inverting input of the amplifier Amp TL According to an embodiment of the present disclosure, the reference limit voltage V TL may be programmable (e.g., via an equivalent Figure 4A or Fig. 6A The control circuit 8354 of the control circuit corresponds to the (predetermined) upper limit temperature T L The voltage V output by the temperature sensor (338) TPA According to another embodiment of the present disclosure, for the voltage V TPA The value of V TPA -V TL ≥0, control voltage A OUT Can be equal to V TPA -V TL , and the control voltage A OUT So the voltage V TPA On the other hand, for voltage V TPA The value of V TPA -V TL <0, control voltage A OUT Therefore, considering that the characteristic response curve of the temperature sensor (338) provides an increasing voltage V for increasing sensed temperature TPA Then for the case below the upper limit temperature T L The sensed value of the temperature, the control voltage A OUT is zero, and therefore the current I SINK On the other hand, for a temperature equal to or higher than the upper limit temperature TL The sensed value of the temperature, the control voltage A OUT Equal to V TPA -V TL , and therefore the current I SINK Can be used with V TPA -V TL Proportional.

[0053] Continue to refer to Fig. 8A , as long as the sensed temperature (e.g., by V TPA indicates) and the upper limit temperature T L (For example, by V TL indicates that there is a non-zero difference between the current I SINK is non-zero. In other words, Figure 8B As shown in the bottom graph, when the current I SINK With reference current I REF When combined, such as Figure 8B The resulting current I OUT_OTP The sensed temperature (eg, PAtemp) may be limited / controlled to a high limit temperature T L It should be noted that by setting the voltage V TPA With voltage V TL The non-inverting terminal and the inverting terminal of the amplifier Amp are reversely coupled to provide over-temperature protection for a temperature sensor (e.g., 338) having a characteristic response curve having a decreasing voltage V for an increasing sensed temperature. TPA Those skilled in the art will recognize that Fig. 8A The configuration can be considered as being able to control / limit the temperature of the PA (such as the sensed temperature) to a high limit temperature T L Closed loop configuration within.

[0054] The teachings of the present disclosure may be extended to controlling bias signals to one or more PA modules for implementing different schemes of over-temperature protection with soft shutdown (e.g., maintaining operation of the PA modules). Fig.9A As shown in , control of the collector current (e.g., Icc2 and / or Icc3) through the PA module (110) can be provided by controlling the bias signal (e.g., voltage or current via circuit I / V Out, 93c) to the respective bases of the emitter follower transistors (Tr22, Tr23). According to an embodiment of the present disclosure, and as Fig.9A As shown in , over-temperature protection may be provided to some, but not necessarily all, of the stages (e.g., 112, 113) of a PA module (e.g., 110). Fig.9AIn an exemplary configuration of , over-temperature protection may be provided to the output driver stage (113) based on a temperature sensor (338) located in close proximity to the stage (113), but over-temperature protection may not be provided to the stage (112), which may be a lower output power stage and which therefore operates at a lower nominal temperature. Fig.9A In the configuration, the voltage V from the temperature sensor (338) TPA can be provided to a circuit block (935), which can first transform the voltage V via circuits (93a, 93b) TPA The above circuit (93a, 93b) may include the above reference Figure 4A , Fig. 6A or Fig. 8A Functionality similar to that described above is therefore provided with reference to e.g. Figure 4B / Figure 4C / Figure 6B / Figure 6C / Figure 8B Any one of the currents described in OUT_OTP Furthermore, the current output by circuits (93a, 93b) can be converted by circuit (93c) into a bias voltage or current which is provided to one or more of the corresponding bases of emitter follower transistors (Tr22, Tr23). Fig.9A As shown in , the collectors of the emitter follower transistors (Tr22, Tr23) can be associated with a (substantially constant, slowly varying) supply voltage (e.g., Vbatt).

[0055] Fig. 9B The above reference Fig.9A A variation of the configuration described, wherein the circuit block (935) is based on a voltage V received from a temperature sensor (338) TPA Directly bias one or more of the stages (112, 113). In such a configuration, the bias signal may be a current (e.g., Fig.9A Ib2 or Ib3) or voltage (for example, Fig. 9C VG1), the shape / contour of the above current or voltage is based on the above reference, for example Figure 4B / Figure 4C / Figure 6B / Figure 6C / Figure 8B Any one of the currents described in OUT_OTP It should be noted that in the case where the PA module (110) comprises one or more stages comprising FET transistors, a Fig. 9BThe circuit block (935) outputs the bias voltage. This is for the case of a stage (e.g., 113) comprising a plurality of series-connected FET transistors (MN1, MN2, ..., MNk) arranged as a cascode stack. Fig. 9C In this case, Fig. 9B The bias voltage output by the circuit block (935) may be a gate voltage VG1, which biases the input transistors (MN1, MN2, ..., MNk) of the common source and common gate stack to provide a bias current Ibias through the common source and common gate stack, wherein the bias current Ibias determines the output power of the stage (113).

[0056] Fig.10 is a process diagram (1000) showing the various steps of a method for controlling current through an amplifier. As can be seen in the process diagram (1000), the method includes: controlling the current to the amplifier based on a detected value of the temperature of the amplifier, such that for detected values ​​of the temperature above a preset temperature limit, the current to the amplifier decreases linearly with respect to increasing temperature detected values, according to step (1010); and reducing the power dissipated through the amplifier for detected values ​​of the temperature above the preset temperature limit, according to step (1020).

[0057] It should be noted that various embodiments of the PA module with over-temperature protection circuit for soft shutdown according to the present disclosure can be implemented as a monolithic integrated circuit (IC) according to any manufacturing technology and process known to those skilled in the art.

[0058] The application of the novel equipment and system that can include various embodiments includes the electronic circuit system used in high-speed computers, communication and signal processing circuit system, modem, single processor module or multi-processor module, single embedded processor or multi-embedded processor, data switch and special modules including multi-layer multi-chip module. Such equipment and system can also be included in various electronic systems as subassemblies, such as television, cellular phone, personal computer (for example, laptop computer, desktop computer, handheld computer, tablet computer, etc.), workstation, radio, video player, audio player (for example, mp3 player), vehicle, medical device (for example, heart monitor, blood pressure monitor, etc.) and other electronic systems. Some embodiments can include various methods.

[0059] The term "MOSFET" technically refers to a metal oxide semiconductor; another synonym for MOSFET is "MISFET" for a metal-insulator-semiconductor FET. However, "MOSFET" has become a generic label for most types of insulated gate FETs ("IGFETs"). Nevertheless, it is well known that the term "metal" in the names MOSFET and MISFET is now generally a misnomer, as the former metal gate material is now generally a polycrystalline silicon (polysilicon) layer. Similarly, the "oxide" in the MOSFET name may be a misnomer, as the purpose of using a different dielectric material is to obtain a strong channel at a smaller applied voltage. Therefore, the term "MOSFET" used in this article should not be understood as being literally limited to metal oxide semiconductors, but rather generally includes IGFETs.

[0060] As should be apparent to those skilled in the art, various embodiments of the present invention can be implemented to meet a variety of specifications. Unless otherwise specified above, the selection of suitable component values ​​is a matter of design choice, and various embodiments of the present invention can be implemented in any suitable IC technology (including but not limited to MOSFET and IGFET structures) or in hybrid or discrete circuit form. Any suitable substrate and process can be used - including but not limited to standard bulk silicon, silicon on insulator (SOI), silicon on sapphire (SOS), GaN HEMT, GaAs pHEMT and MESFET technology - to manufacture integrated circuit embodiments. However, the above-mentioned inventive concept is particularly useful for SOI-based manufacturing processes (including SOS) and manufacturing processes with similar characteristics. CMOS manufacturing on SOI or SOS achieves low power consumption, the ability to withstand high power signals during operation due to FET stacking, good linearity and high frequency operation (more than about 10GHz, and particularly above about 20GHz). Monolithic IC implementations are particularly useful because parasitic capacitance can usually be kept low (or kept to a minimum, consistent between all units, thereby allowing compensation for parasitic capacitance) by careful design.

[0061] Depending on the particular specification and / or implementation technology (e.g., NMOS, PMOS, or CMOS and enhancement mode or depletion mode transistor devices), voltage levels may be adjusted and / or voltage and / or logic signal polarity may be inverted. Component voltage handling capabilities, current handling capabilities, and power handling capabilities may be adjusted as desired, for example, by adjusting device size, "stacking" components (particularly FETs) in series to withstand higher voltages, and / or by using multiple components in parallel to handle higher currents. Additional circuit components may be added to enhance the capabilities of the disclosed circuits and / or to provide additional functionality without significantly changing the functionality of the disclosed circuits.

[0062] The examples set forth above are provided to provide a person of ordinary skill in the art with a complete disclosure and description of embodiments of the gate driver of the stacked transistor amplifier of the present disclosure on how to make and use the present disclosure, and are not intended to limit the scope of the invention as viewed by the applicant. Such embodiments may be used, for example, in mobile phones of current communication systems (e.g., WCDMA, LTE, 5G, WiFi, etc.), where it may be necessary to amplify signals with frequency content above 100 MHz and power levels above 50 mW. A skilled person may find other suitable implementations of the presented embodiments.

[0063] Modifications to the above-described modes for carrying out the methods and systems disclosed herein that are obvious to those skilled in the art are intended to fall within the scope of the appended claims. All patents and publications mentioned in the specification are indicative of the technical levels of those skilled in the art to which the present disclosure belongs. All references cited in the present disclosure are incorporated by reference to the same extent as if each reference had been individually incorporated by reference in its entirety.

[0064] It should be understood that the present disclosure is not limited to a particular method or system, which can certainly vary. It should also be understood that the terms used herein are for the purpose of describing a particular embodiment only and are not intended to be limiting. As used in this specification and the appended claims, unless the context clearly indicates otherwise, the singular forms of "one", "an" and "the" include plural referents. Unless the context clearly indicates otherwise, the term "multiple" includes two or more referents. Unless otherwise defined, all technical terms and scientific terms used herein have the same meanings as those of ordinary skill in the art to which the present disclosure belongs.

[0065] A number of embodiments of the present disclosure have been described. However, it will be appreciated that various modifications may be made without departing from the spirit and scope of the present disclosure. Therefore, other embodiments are within the scope of the appended claims.

Claims

1. A circuit comprising: a bias circuit configured to supply a bias signal based on the control current; as well as a protection circuit configured to detect a temperature and generate the control current according to the detected temperature, Among them, for: i) the detected temperature is below a preset high temperature limit, the control current is constant, and ii) above the detected temperature of the preset high temperature limit, the control current is a linear function of the detected temperature, the linear function having a negative slope with increasing values ​​of the detected temperature.

2. The circuit according to claim 1, wherein The circuit also includes an amplifier, and The bias circuit is configured to supply the bias signal to the amplifier.

3. The circuit according to claim 2, wherein: The detected temperature is the local temperature sensed by a temperature sensor located in close proximity to the amplifier.

4. The circuit according to claim 2, wherein: The detected temperature is the ambient temperature sensed by a temperature sensor located remote from the amplifier.

5. The circuit according to claim 2, wherein: The bias circuit includes an emitter follower transistor configured to supply the bias signal to the amplifier.

6. The circuit according to claim 5, wherein: The control current is provided to the collector of the emitter follower transistor.

7. The circuit according to claim 5, wherein: The control current is provided to the base of the emitter follower transistor.

8. The circuit according to claim 2, wherein: The amplifier comprises a cascode stack of FET transistors connected in series, and A voltage proportional to the control current is provided to the gates of the input transistors of the cascode stack.

9. The circuit according to claim 2, wherein: The amplifier comprises a first amplifier stage, a bias current through the first amplifier stage based on the bias signal, and The bias signal is configured to control power dissipation through the first amplifier stage to be below a thermal breakdown limit of the first amplifier stage.

10. The circuit according to claim 2, wherein: The control current is based on a combination of: a reference current generated by a reference current source independent of the detected temperature, the reference current being constant, and Sink current, where for: i) the detected temperature is below the preset high temperature limit, the sink current is zero, and ii) above the detected temperature of the preset high temperature limit, the sink current is a linear function of the detected temperature, the linear function having a positive slope with respect to increasing values ​​of the detected temperature, the positive slope having the same magnitude as the negative slope of the control current.

11. The circuit according to claim 10, wherein: The control current is based on subtracting the sink current from the reference current.

12. The circuit according to claim 10, wherein: The protection circuit comprises: a first current source configured to generate a current proportional to the detected temperature; a second current source connected in series with the first current source; and a first current mirror, comprising a reference current branch and a target current branch, wherein the reference current branch is connected in series with one of the second current source or the first current source, wherein when the detected temperature is higher than the preset high temperature limit, a non-zero current based on a difference between a current generated by the first current source and a current generated by the second current source flows through the reference current branch of the first current mirror, and otherwise no current flows through the reference current branch, and The injection current flows through the target current branch of the first current mirror.

13. The circuit of claim 12, wherein: The current generated by the second current source is programmable and is based on a value of the preset high temperature limit.

14. The circuit of claim 12, wherein: A ratio of current through the target current branch relative to current through the reference current branch of the first current mirror provides the positive slope.

15. The circuit of claim 14, wherein: The ratio is programmable.

16. The circuit of claim 10, wherein: The protection circuit comprises: a temperature sensor configured to output a detected temperature voltage based on a characteristic response curve of the temperature sensor; an error amplifier having a first input terminal coupled to the detected temperature voltage and a second input terminal coupled to a reference limit voltage, the reference limit voltage corresponding to the preset high temperature limit in the characteristic response curve; A first current source is coupled to the output of the error amplifier, and is configured to generate the sink current based on a difference between the detected temperature voltage and the reference limit voltage.

17. The circuit of claim 9, wherein: The amplifier comprises a second amplifier stage, the second amplifier stage being arranged in cascade with the first amplifier stage, and A bias current through the second amplifier stage is based on the bias signal.

18. The circuit of claim 2, further comprising additional one or more amplifiers and additional corresponding one or more bias circuits configured to supply corresponding bias signals, in, At any given time, the circuit processes the RF signal through only one of the additional one or more amplifiers and the amplifier, and Wherein the protection circuit is further configured to generate the control current based on an amplifier-specific preset high temperature limit and a negative slope of the control current based on the detected temperature.

19. The circuit of claim 18, wherein: The temperature detected is the ambient temperature.

20. The circuit of claim 1, wherein: The circuit is monolithically integrated.

21. The circuit of claim 1, wherein: The circuit is monolithically integrated with a temperature sensor.

22. A power amplifier module comprising the circuit according to claim 1.

23. A method for controlling current through an amplifier, the method comprising: controlling a current to the amplifier based on a detected value of a temperature of the amplifier such that for detected values ​​of the temperature above a preset temperature limit, the current to the amplifier decreases linearly with increasing detected values ​​of the temperature, and Based on the controlling, for detected values ​​of the temperature above the preset temperature limit, power dissipated by the amplifier is reduced.

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