US20180159518A1 - Ringing peak detector module for an inductive electric load driver, related system and integrated circuit - Google Patents
Ringing peak detector module for an inductive electric load driver, related system and integrated circuit Download PDFInfo
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
- H03K5/153—Arrangements in which a pulse is delivered at the instant when a predetermined characteristic of an input signal is present or at a fixed time interval after this instant
- H03K5/1532—Peak detectors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
- H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
- H02P27/085—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
- H02P7/02—Arrangements for regulating or controlling the speed or torque of electric DC motors the DC motors being of the linear type
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
- H02P7/02—Arrangements for regulating or controlling the speed or torque of electric DC motors the DC motors being of the linear type
- H02P7/025—Arrangements for regulating or controlling the speed or torque of electric DC motors the DC motors being of the linear type the DC motors being of the moving coil type, e.g. voice coil motors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
- H02P7/03—Arrangements for regulating or controlling the speed or torque of electric DC motors for controlling the direction of rotation of DC motors
- H02P7/04—Arrangements for regulating or controlling the speed or torque of electric DC motors for controlling the direction of rotation of DC motors by means of a H-bridge circuit
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/16—Modifications for eliminating interference voltages or currents
- H03K17/161—Modifications for eliminating interference voltages or currents in field-effect transistor switches
- H03K17/165—Modifications for eliminating interference voltages or currents in field-effect transistor switches by feedback from the output circuit to the control circuit
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
- H03K17/689—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors with galvanic isolation between the control circuit and the output circuit
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K7/00—Modulating pulses with a continuously-variable modulating signal
- H03K7/08—Duration or width modulation ; Duty cycle modulation
Definitions
- Embodiments of the present disclosure relate to solutions concerning a ringing peak detector module for detecting a ringing at the output of an inductive electric load driver, in particular a DC motor driver, including a ringing peak detector circuit configured to detect a peak value of an oscillation taking in place on the inductive electric load, and a module configured to compare the detected peak value with a maximum value, and to command the driver by an error signal calculated as a function of the difference between the peak value and maximum value.
- Inductive electrical loads such as DC motors, in particular brushless DC motors, are often controlled by means of pulse-width-modulation (PWM) in order to adjust an electric current and/or an electric voltage for the respective electrical load.
- PWM pulse-width-modulation
- an electrical load is often coupled in a resonant full-bridge or half-bridge circuit to electronic components such as metal-oxide semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs) which are switched on and off under the control of the PWM signal and, as a result, adjust the current and/or the voltage for the electrical load.
- MOSFETs metal-oxide semiconductor field-effect transistors
- IGBTs insulated-gate bipolar transistors
- a motor is often driven by means of one or more half-bridges as a function of one or more respective PWM signals.
- FIG. 1 shows a typical half-bridge circuit or arrangement 20 including two electronic switches SW 1 and SW 2 , such as n-channel power MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), connected in series between a supply voltage Vdd and a ground GND.
- n-channel power MOSFETs Metal-Oxide-Semiconductor Field-Effect Transistor
- the switches SW 1 and SW 2 are closed alternatively in order to connect the output OUT of the half-bridge arrangement 20 , i.e., the intermediate point between the switches SW 1 and SW 2 , either to the voltage Vdd or to ground GND.
- the half-bridge arrangement 20 is driven as a function of two drive signals DRV 1 and DRV 2 , which are connected (e.g., directly) to the control gates of the switches SW 1 and SW 2 , respectively.
- a high-side driver 200 1 is used to generate the drive signal DRV 1 for the high-side switch SW 1 as a function of a first control signal IN 1
- a low-side driver 200 2 is used to generate the drive signal DRV 2 for the low-side switch SW 2 as a function of a control signal IN 2 .
- the control signal IN 2 corresponds often to an inverted version of the signal IN 1 (or vice versa), i.e., the signal IN 2 is low when the signal IN 1 is high and vice versa.
- an inverter 202 is used which receives at an input the signal IN 1 and provides at an output the signal IN 2 .
- the output OUT of the half-bridge arrangement 20 may be used to drive a load.
- the half-bridge arrangement 20 drives a motor M 1 connected between the output OUT of the half-bridge arrangement 20 and ground GND.
- FIG. 3 shows an example in which three half-bridge arrangements 20 a , 20 b and 20 c controlled by respective control signals IN a , IN b and IN c are used to drive a three-phase motor M 3 , such as a spindle motor, connected between the outputs OUT a , OUT b and OUT c of the half-bridge arrangements 20 a , 20 b and 20 c .
- a three-phase motor M 3 such as a spindle motor
- control signals IN, or IN a and IN b , or IN a , IN b and IN c may be PWM signals, i.e., signals with a fixed frequency and a variable duty cycle.
- a ringing analyzer module 300 includes a peak detector circuit 310 which receives at an input the PWM control signal IN 2 and also receives a differential input.
- the peak detector circuit 310 outputs a peak value pv which, after the subtraction with a steady-state value ss, is brought as ringing peak pr to an input of a subtraction block 320 to perform the difference with a predefined setpoint sp, brought at the other input of the subtraction block 320 , which represents the maximum allowable ringing.
- a ringing error signal re is obtained, which is then sent to command the low-side driver 200 2 , which drives the gate of the low-side switch SW 2 .
- the low side driver 200 2 is configured to generate a pattern of gate current or a gate voltage in synchronous with the rising and falling edges of the PWM signal IN 2 .
- the ringing error signal re can be used by the low side driver 200 2 to command variations of such pattern of gate current or gate voltage so that the peak value pv is reduced.
- a method and device for switching an electronic component on or off under the control of a pulse-width-modulation signal which uses such solution.
- the ringing error signal is used to vary switchover times to different levels of gate current or gate voltage so to decrease the amplitude of the oscillations if their peak is greater than the setpoint sp.
- the differential input SLx-SLy is proportional to the drain source voltage of the low side switches, since each of the signals of the differential pair, SLx or Sly, is taken at the output of the low-side switch of the half-bridge of a given phase.
- FIG. 5 is depicted an example with reference to a driver with three phases, like in FIG.
- the pair of signals SL x and Sl y of FIG. 4 can correspond to any of such three pairs, or to a difference of two signals, in the case of FIG. 2 , or also one of the two signals can be zero, in the case of FIG. 1 , i.e., the ringing analyzer 300 receives only one input, the other being zero.
- the input waveform at the peak detector i.e., the waveform determined by the differential pair SL x and Sl y
- the waveform determined by the differential pair SL x and Sl y has a (functional) common mode between ⁇ 1V and +1V (and an absolute between ⁇ 6V and +6V), with a differential amplitude that can reach 3V. Therefore, the overall voltage range is outside the 3.3V CMOS Safe Operating Area (SOA).
- SOA CMOS Safe Operating Area
- Embodiments moreover concern a related method and integrated circuit.
- the present disclosure relates to a ringing peak detector module for detecting a ringing at the output of an inductive electric load driver, in particular a DC motor driver including a resonant full-bridge or half-bridge circuit including one or more high side electronic switches and one or more low side switches, in particular MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), connected in series between a supply voltage and a ground, a ringing peak detector circuit receiving a differential input obtained by a pair of feedback signals representative of the drain-source voltage of a low-side switch, configured to detect the peak value of an oscillation of the current and/or voltage taking in place on the inductive electric load, and a module configured to compare a ringing peak, corresponding to the difference between the detected peak value and the steady-state, with a predefined maximum value, commanding the inductive electric load driver by an error signal calculated as a function of the difference between the ringing peak value and maximum value.
- MOSFETs Metal-O
- the ringing peak detector module includes an input buffer module, placed upstream the peak detector circuit, configured to shift the feedback signals of the differential input so that the common mode of the differential input is centered at a half-dynamic level, which is half of the supply voltage Vdd, providing as output for the input of a peak detector circuit a shifted differential output, which maintains a steady-state value of the differential input signal.
- the peak detection module includes an input buffer which includes input capacitors connected in series on each of its input pins receiving the pair of feedback signals forming the differential input, the capacitors being configured to sustain the input voltage range.
- An analog to digital differential module receives as an input one of the shifted voltage signals and the output signal of the peak detector, and supplies as an output their digital difference.
- the input buffer includes a shift module configured to connect the signals at its differential inputs to a half voltage corresponding to the half-dynamic level of the supply voltage.
- the input buffer includes a module configured to switch the polarity of differential signals at its differential inputs.
- the input buffer is connected to the input capacitors and the shift module is connected to the outputs of the input buffer.
- the peak detector circuit includes a differential amplifier receiving as input one of the shifted voltages and its output signals to control the charge of a peak capacitor to store the peak voltage.
- the steady-state voltage is subtracted from the detected peak value in order to obtain the ringing peak signal.
- the module is configured to compare the detected ringing peak with a maximum value, commanding the driver by an error signal calculated as a function of the difference between the ringing peak and maximum value includes a subtraction block configured to perform a subtraction between the detected peak value and with the predefined maximum value in order to obtain the error signal to command the gate of the low-side switch.
- the input buffer includes a set point circuit configured to add a voltage corresponding to the predefined maximum value to the differential output voltage of the input buffer.
- the set point circuit includes a set-point store capacitor connected at one end at the node on which the negative shifted voltage forms and the other is connected through a first switch to an input receiving the maximum value and through a second switch to ground, the set point circuit being configured to connect to the set-point store capacitor to the predefined maximum value to add a voltage corresponding to the predefined maximum value to the differential output voltage of the input buffer so that is equal to the sum of the steady-state voltage of the differential input and of the predefined maximum value.
- the present disclosure relates also to a system including an inductive electric load driver, in particular a DC motor driver including a resonant full-bridge or half-bridge circuit including high side electronic switches and low side switches, in particular MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), connected in series between a supply voltage and a ground, and a peak detection module for detecting a ringing at the output of the inductive electric load driver as described above.
- MOSFETs Metal-Oxide-Semiconductor Field-Effect Transistor
- the present disclosure relates also to an integrated circuit including the peak detector module detection circuit or the system as described above.
- FIGS. 1 to 5 show embodiments of conventional drivers and ringing peak detector circuits
- FIG. 6 shows an embodiment of a ringing peak detection module
- FIG. 7 shows a second embodiment of a ringing peak detection module
- FIG. 8 shown a time diagram of quantities formed in the ringing peak detection module.
- a possible solution could be the use of an internal capacitor and an adder operational amplifier to perform all the necessary math operations, however the architecture of the peak detector in this way becomes complex to be designed, since there is the need to store the steady-state value of the input, store the peak value of the input, compute the peak value minus steady-state to obtain the peak of the ringing, subtract then in the sum block following the peak detector the set-point to obtain the ringing error to drive the gate.
- FIGS. 6 and 7 elements or components which have already been described with reference to FIGS. 1 to 5 are denoted by the same references previously used in such figures. The description of such previously described elements will not be repeated in the following in order not to overburden the present detailed description.
- the present disclosure relates to a ringing peak detector module for detecting a ringing at the output of an inductive electric load driver, in particular a DC motor driver.
- FIG. 6 shows the general architecture of a ringing peak detector module 400 in accordance with the present disclosure.
- the peak detector module 400 includes an input buffer module 412 to shift and possibly invert the differential input SLx-SLy, with a common mode of the differential input SLx-SLy centered at the half-dynamic level of the supply voltage, which in the example is 1.65V.
- the input buffer module 412 includes input capacitors Cx, Cy connected in series on each of the input pins receiving the pair of feedback signals SLx, SLy forming the differential input SLx-Sly.
- feedback signal SLx which may for instance correspond to signal Sla in FIG. 3
- signal SLy which may for instance correspond to signal SLb in FIG. 3
- Such input capacitors Cx, Cy allow sustaining the input voltage range, so that it is possible to use a complete CMOS 3.3V architecture.
- a module 412 a to select the polarity of the input differential signals SLx, Sly including an arrangement of switches configured to switch upon selection the connections of the feedback signals SLx and SLy to the inputs of a following module, specifically a following shift module 412 b.
- the shift module 412 b is configured through a respective arrangement of switches to selectively connect the input differential signals SLx, Sly, according to the polarity selected in block 412 a , to a half voltage Vhd corresponding to the half-dynamic level of the supply voltage, e.g., 1.65 V for 3.3V CMOS. This initialization is needed because the input buffer 412 is designed to follow the differential variations of the input signal, but is not able to set the DC starting point of the two signals related to GND.
- the input buffer module 412 supplies a shifted differential output formed by a pair of voltage shifted signals, Vs 1 and Vs 2 , where Vs 1 indicates the shifted positive signal and Vs 2 the shifted negative signal.
- the input buffer module 412 is configured to supply a buffered differential output, Vs 1 -Vs 2 , corresponding to the steady state value ss of the differential input SLx-Sly.
- the ringing peak detector module 400 then includes the peak detector circuit 310 , which receives at its inputs the two signals of the differential output Vs 1 , Vs 2 of the input buffer module 412 , in place of the input differential signals SLx, SLy, and supplies an output voltage Vpout corresponding to the peak of the such buffered differential output Vs 1 -Vs 2 .
- the positive shifted signal Vs 1 is brought to the inverting input of a differential amplifier 315 while the negative shifted signal Vs 2 is brought to a floating ground line FG.
- the positive input of the differential amplifier 315 is connected to the output node Vout of the circuit 310 .
- a current mirror 316 is connected to the CMOS voltage supply VCC (i.e., is connected between the output of the differential amplifier 315 and output node pout), the diode connected transistor of the current mirror 316 receiving the output current of the differential amplifier 315 and the output of the other transistor of the current mirror 316 generating the output voltage Vpout.
- a peak capacitor C peak to store the peak voltage, is connected between the output node pout and the floating ground line FG.
- the current mirror 316 charges the peak capacitor C peak .
- the amplifier 315 enables the current mirror 316 to charge the peak capacitor C peak .
- the amplifier 315 shuts off the current mirror 316 and the output is held at the peak value, i.e., peak voltage, on the peak capacitor C peak .
- the peak detector 310 is a circuit which is known to the person skilled in the art and the peak detector circuit of FIG. 6 can be substituted with other topologies of peak detector circuits performing corresponding functions.
- an output voltage Vpout on the output node pout of the circuit 310 is brought to a differential analog to digital converter (ADC) 418 , which receives at its inputs such output voltage Vpout and the positive shifted voltage Vs 1 .
- ADC analog to digital converter
- the input buffer module 412 is able to keep the steady-state value ss of the differential input, i.e., the difference SLx-SLy, which is stored in the differential shifted output voltage (Vs 1 ⁇ Vs 2 ).
- the peak voltage is stored in the differential voltage Vpout ⁇ Vs 2 .
- the ringing peak pr which is the difference between the peak voltage and the steady state ss of the input differential signal, is equal to
- differential analog to digital converter 418 it is possible to convert directly the ringing peak signal, as the differential voltage between the output voltage Vpout and the shifted positive input Vs 1 , without any additional operation.
- the output signal of the differential ADC 418 i.e., the detected ringing peak pr, can be then sent to the subtraction block 320 to perform a subtraction with the predefined set-point sp, which represents the maximum allowable ringing, in order to obtain a ringing error re to command the gate of the low-side switch SW 2 .
- a set point circuit 419 is added to the input buffer 412 .
- Such set point circuit 419 includes a set-point store capacitor C 2 , which is connected at one end at the node on which the negative shifted voltage Vs 2 forms and the other is connected through a first switch 421 to an input receiving the set-point sp and through a second switch 422 to ground.
- the capacitance value of the set-point store capacitor C 2 is equal to the capacitance value of each of the input capacitors Cx, Cy.
- the input buffer 412 is able to keep at its output the steady-state value ss of the differential input SLx ⁇ SLy, stored in its differential output voltage Vs 1 ⁇ Vs 2 .
- the differential ADC 418 At the input of the differential ADC 418 , it is obtained a voltage equal to (Vpout ⁇ Vs 2 ) ⁇ (Vs 1 -Vs 2 ); as the difference between Vs 1 and Vs 2 is equal to the steady-state voltage ss summed to the set-point sp, then at the input of the differential ADC 418 it is obtained a voltage which corresponds to the peak voltage of the differential input signal SLx ⁇ Sly, minus the steady state of such input signal, SLx ⁇ SLy minus the set point sp. More briefly:
- ADC input peak voltage pv ⁇ (steady-state voltage ss +set-point sp )
- ADC input peak voltage pv ⁇ steady-state voltage ss ⁇ set-point sp
- the ringing error re can be supplied directly to the gate driver 200 2 without using the subtraction block 320 .
- the input buffer 412 is able to maintain the steady state value ss of the input differential signal, since it follows the variations, also very slow variations, of the differential input, in addition to shifting the common mode voltage to the half-dynamic level.
- the peak value pv is the peak of the differential signal with respect to the differential zero voltage (Vpout-Vs 2 ).
- the peak ringing pr is the difference between the peak value pv and the steady state value ss, which can be different from 0V. Peak ringing pr represents the peak of the oscillation that it is desired to reduce. This allows automatically computing the peak ringing pr by directly connecting the voltages Vpout and Vs 1 to the analog to digital converter 418 .
- the ringing peak detection module by the input buffer is able to maintain the regime value of the differential signal, since it follows the variations, also very slow variation, of the differential input, in addition to shift the common mode voltage to the half-dynamic level.
- FIG. 8 shows a time diagram of quantities formed in the ringing peak detection module.
- the pair of feedback signals SLx (dotted line) and SLy (dashed line) are represented as a function of time.
- the feedback signal SLx presents a sinusoidal wave, i.e., a differential event, between ⁇ 100 mV and 100 my, while feedback signal SLy is zero and remains equal to zero, i.e., it is connected to the source of a non-switching MOS.
- the signal SLy is zero, since it is connected to a branch which does not switch.
- the circuit described with reference to FIG. 5 to drive a three-phase motor, is based on the assumption that only one MOS at a time switches. In the example of FIG. 8 SLx is connected to the branch which is currently switching.
- Vs 1 dotted line
- Vs 2 dashed line
- the solution here disclosed allows architecture simplification and use of a standard CMOS structure to design the core block.
- the solution here described can be applied when a ringing peak detector, able to work at high frequencies, in a voltage range outside standard CMOS operating area, is needed, for instance in BLDC motor drivers.
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Abstract
A ringing peak detector module detects a ringing at the output of an inductive load driver including a bridge circuit containing high side and low side switches. A ringing peak detector receives differential feedback signals representative of the drain-source voltage of the low-side switch and detects a ringing peak of an oscillation of a current/voltage on the inductive load. A module compares said detected ringing peak with a maximum value and controls said driver by an error signal calculated as a function of the difference between said peak value and maximum value. The ringing peak detector module includes an input buffer module upstream of said peak detector circuit that shifts the differential feedback signals so a common mode of these signals is centered at a half-dynamic level of a supply voltage to provide correspondingly shifted voltages forming a shifted differential output corresponding to a steady state of the differential feedback signals.
Description
- Embodiments of the present disclosure relate to solutions concerning a ringing peak detector module for detecting a ringing at the output of an inductive electric load driver, in particular a DC motor driver, including a ringing peak detector circuit configured to detect a peak value of an oscillation taking in place on the inductive electric load, and a module configured to compare the detected peak value with a maximum value, and to command the driver by an error signal calculated as a function of the difference between the peak value and maximum value.
- In automotive applications the use of Direct Current (DC) or Brushless DC (BLDC) motors for fan, pump or actuator applications is very common with the trend of replacing the traditional DC with BLDC motors.
- Inductive electrical loads such as DC motors, in particular brushless DC motors, are often controlled by means of pulse-width-modulation (PWM) in order to adjust an electric current and/or an electric voltage for the respective electrical load. For this purpose, an electrical load is often coupled in a resonant full-bridge or half-bridge circuit to electronic components such as metal-oxide semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs) which are switched on and off under the control of the PWM signal and, as a result, adjust the current and/or the voltage for the electrical load.
- A motor is often driven by means of one or more half-bridges as a function of one or more respective PWM signals.
- For example,
FIG. 1 shows a typical half-bridge circuit orarrangement 20 including two electronic switches SW1 and SW2, such as n-channel power MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), connected in series between a supply voltage Vdd and a ground GND. - Usually, the switches SW1 and SW2 are closed alternatively in order to connect the output OUT of the half-
bridge arrangement 20, i.e., the intermediate point between the switches SW1 and SW2, either to the voltage Vdd or to ground GND. - For this purpose, the half-
bridge arrangement 20 is driven as a function of two drive signals DRV1 and DRV2, which are connected (e.g., directly) to the control gates of the switches SW1 and SW2, respectively. - Specifically, in order to correctly drive the control gates, usually a high-
side driver 200 1 is used to generate the drive signal DRV1 for the high-side switch SW1 as a function of a first control signal IN1, and a low-side driver 200 2 is used to generate the drive signal DRV2 for the low-side switch SW2 as a function of a control signal IN2. - The control signal IN2 corresponds often to an inverted version of the signal IN1 (or vice versa), i.e., the signal IN2 is low when the signal IN1 is high and vice versa. For example, in
FIG. 1 aninverter 202 is used which receives at an input the signal IN1 and provides at an output the signal IN2. - The output OUT of the half-
bridge arrangement 20 may be used to drive a load. For example, inFIG. 1 , the half-bridge arrangement 20 drives a motor M1 connected between the output OUT of the half-bridge arrangement 20 and ground GND. - Conversely,
FIG. 2 shows an example in which two half-bridge arrangements first bridge arrangement 20 a and the output OUTb of thesecond bridge arrangement 20 b. As well known to those of skill in the art, in this case, also the rotation direction of the motor M2 may be controlled by applying appropriate control signals INa and INb to the half-bridge arrangements - Finally,
FIG. 3 shows an example in which three half-bridge arrangements bridge arrangements - As mentioned before, the control signals IN, or INa and INb, or INa, INb and INc may be PWM signals, i.e., signals with a fixed frequency and a variable duty cycle.
- When electronic components such as this are switched on and off, undesired parasitic oscillations of the current and the voltage, which can negatively affect the electromagnetic compatibility of the circuit and cause switching losses, can occur.
- More in particular, there is the necessity to keep conducted emissions under a certain level, in a motor driver application. Conducted emission requirements are violated only in the frequency range where a ringing takes place. Ringing is an oscillation present at any terminal of an external MOS, caused by reverse recovery charge of the body diodes or by high di/dt or dv/dt.
- In order to reduce parasitic oscillations, it is known to connect external capacitors to the gate and source or drain of the electronic components, gate resistors to reduce rates of change of the gate current and to use gate voltage or suppressor circuits for oscillation damping. Connection of such electrical components has several drawbacks, such as lengthening the switching times and increase the switching losses, switching delays and manufacturing costs.
- Another known solution provides measuring the peak of the ringing at the output of the MOS transistor driving the motor or the electric load and subtracting from such peak a predefined set-point value, representing a maximum allowable ringing, in order to drive properly the gate of the external MOS, i.e., the electric component.
- Such solution is schematized in
FIG. 4 , in which it is shown the low-side driver 200 2 ofFIG. 1 used to generate the drive signal DRV2 for the low-side switch SW2 as a function of a control signal, i.e., PWM signal, IN2. InFIG. 4 it is also shown a shunt inductance RS connected between the source of the low-side switch SW2 and the ground. - A
ringing analyzer module 300 includes apeak detector circuit 310 which receives at an input the PWM control signal IN2 and also receives a differential input. The differential input, SLx−Sly, obtained by a pair of feedback signals SLx and SLy, representative of the drain-source voltage of the low-side switch SW2. - The
peak detector circuit 310 outputs a peak value pv which, after the subtraction with a steady-state value ss, is brought as ringing peak pr to an input of asubtraction block 320 to perform the difference with a predefined setpoint sp, brought at the other input of thesubtraction block 320, which represents the maximum allowable ringing. From the subtraction at block 320 a ringing error signal re is obtained, which is then sent to command the low-side driver 200 2, which drives the gate of the low-side switch SW2. Thelow side driver 200 2 is configured to generate a pattern of gate current or a gate voltage in synchronous with the rising and falling edges of the PWM signal IN2. The ringing error signal re can be used by thelow side driver 200 2 to command variations of such pattern of gate current or gate voltage so that the peak value pv is reduced. - For instance, in US 2015/0349772 A1, a method and device are described for switching an electronic component on or off under the control of a pulse-width-modulation signal which uses such solution. The ringing error signal is used to vary switchover times to different levels of gate current or gate voltage so to decrease the amplitude of the oscillations if their peak is greater than the setpoint sp.
- The differential input SLx-SLy is proportional to the drain source voltage of the low side switches, since each of the signals of the differential pair, SLx or Sly, is taken at the output of the low-side switch of the half-bridge of a given phase. In
FIG. 5 is depicted an example with reference to a driver with three phases, like inFIG. 3 , where there are therefore threepeak detectors 310 connected between each one of the three-halfbridges - The pair of signals SLx and Sly of
FIG. 4 can correspond to any of such three pairs, or to a difference of two signals, in the case ofFIG. 2 , or also one of the two signals can be zero, in the case ofFIG. 1 , i.e., theringing analyzer 300 receives only one input, the other being zero. - This type of solution presents at least two inconveniences.
- In the first place the input waveform at the peak detector, i.e., the waveform determined by the differential pair SLx and Sly, has a (functional) common mode between −1V and +1V (and an absolute between −6V and +6V), with a differential amplitude that can reach 3V. Therefore, the overall voltage range is outside the 3.3V CMOS Safe Operating Area (SOA). This can be solved using a high voltage switch at the input, with either 3.3V floating rails (to work with CMOS circuits) or use of cascodes, however it is difficult to guarantee precision and speed.
- In view of the above, of the present disclosure provides solutions which overcome one or more of the above drawbacks.
- Embodiments moreover concern a related method and integrated circuit.
- The claims are an integral part of the technical teaching of the disclosure provided herein.
- As mentioned before, the present disclosure relates to a ringing peak detector module for detecting a ringing at the output of an inductive electric load driver, in particular a DC motor driver including a resonant full-bridge or half-bridge circuit including one or more high side electronic switches and one or more low side switches, in particular MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), connected in series between a supply voltage and a ground, a ringing peak detector circuit receiving a differential input obtained by a pair of feedback signals representative of the drain-source voltage of a low-side switch, configured to detect the peak value of an oscillation of the current and/or voltage taking in place on the inductive electric load, and a module configured to compare a ringing peak, corresponding to the difference between the detected peak value and the steady-state, with a predefined maximum value, commanding the inductive electric load driver by an error signal calculated as a function of the difference between the ringing peak value and maximum value. The ringing peak detector module includes an input buffer module, placed upstream the peak detector circuit, configured to shift the feedback signals of the differential input so that the common mode of the differential input is centered at a half-dynamic level, which is half of the supply voltage Vdd, providing as output for the input of a peak detector circuit a shifted differential output, which maintains a steady-state value of the differential input signal. The peak detection module includes an input buffer which includes input capacitors connected in series on each of its input pins receiving the pair of feedback signals forming the differential input, the capacitors being configured to sustain the input voltage range. An analog to digital differential module receives as an input one of the shifted voltage signals and the output signal of the peak detector, and supplies as an output their digital difference.
- In various embodiments, the input buffer includes a shift module configured to connect the signals at its differential inputs to a half voltage corresponding to the half-dynamic level of the supply voltage.
- In various embodiments, the input buffer includes a module configured to switch the polarity of differential signals at its differential inputs.
- In various embodiments, the input buffer is connected to the input capacitors and the shift module is connected to the outputs of the input buffer.
- In various embodiments, the peak detector circuit includes a differential amplifier receiving as input one of the shifted voltages and its output signals to control the charge of a peak capacitor to store the peak voltage.
- In various embodiments, the steady-state voltage is subtracted from the detected peak value in order to obtain the ringing peak signal.
- In various embodiments, the module is configured to compare the detected ringing peak with a maximum value, commanding the driver by an error signal calculated as a function of the difference between the ringing peak and maximum value includes a subtraction block configured to perform a subtraction between the detected peak value and with the predefined maximum value in order to obtain the error signal to command the gate of the low-side switch.
- In various embodiments, the input buffer includes a set point circuit configured to add a voltage corresponding to the predefined maximum value to the differential output voltage of the input buffer.
- In various embodiments, the set point circuit includes a set-point store capacitor connected at one end at the node on which the negative shifted voltage forms and the other is connected through a first switch to an input receiving the maximum value and through a second switch to ground, the set point circuit being configured to connect to the set-point store capacitor to the predefined maximum value to add a voltage corresponding to the predefined maximum value to the differential output voltage of the input buffer so that is equal to the sum of the steady-state voltage of the differential input and of the predefined maximum value.
- The present disclosure relates also to a system including an inductive electric load driver, in particular a DC motor driver including a resonant full-bridge or half-bridge circuit including high side electronic switches and low side switches, in particular MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), connected in series between a supply voltage and a ground, and a peak detection module for detecting a ringing at the output of the inductive electric load driver as described above.
- The present disclosure relates also to an integrated circuit including the peak detector module detection circuit or the system as described above.
- Embodiments of the present disclosure will now be described with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:
-
FIGS. 1 to 5 show embodiments of conventional drivers and ringing peak detector circuits; -
FIG. 6 shows an embodiment of a ringing peak detection module; -
FIG. 7 shows a second embodiment of a ringing peak detection module; -
FIG. 8 shown a time diagram of quantities formed in the ringing peak detection module. - In the following description, numerous specific details are given to provide a thorough understanding of embodiments. The embodiments can be practiced without one or several specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments.
- Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
- The headings provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
- There is the need to store the peak value pv and the steady-state value ss of the input waveform in the peak detector, to calculate the ringing peak pr and subtract the set-point. A high frequency ringing (for instance 40-60 MHz), with a small amplitude (for instance ˜50-100 mV) as compared to the total voltage swing of the entire input waveform can be critical as well as the polarity management, since the peak detector works only with rising signals. A possible solution could be the use of an internal capacitor and an adder operational amplifier to perform all the necessary math operations, however the architecture of the peak detector in this way becomes complex to be designed, since there is the need to store the steady-state value of the input, store the peak value of the input, compute the peak value minus steady-state to obtain the peak of the ringing, subtract then in the sum block following the peak detector the set-point to obtain the ringing error to drive the gate.
- In the following
FIGS. 6 and 7 parts, elements or components which have already been described with reference toFIGS. 1 to 5 are denoted by the same references previously used in such figures. The description of such previously described elements will not be repeated in the following in order not to overburden the present detailed description. - As mentioned in the foregoing, the present disclosure relates to a ringing peak detector module for detecting a ringing at the output of an inductive electric load driver, in particular a DC motor driver.
-
FIG. 6 shows the general architecture of a ringingpeak detector module 400 in accordance with the present disclosure. - In the embodiment considered, the
peak detector module 400 includes aninput buffer module 412 to shift and possibly invert the differential input SLx-SLy, with a common mode of the differential input SLx-SLy centered at the half-dynamic level of the supply voltage, which in the example is 1.65V. - The
input buffer module 412 includes input capacitors Cx, Cy connected in series on each of the input pins receiving the pair of feedback signals SLx, SLy forming the differential input SLx-Sly. In this case feedback signal SLx, which may for instance correspond to signal Sla inFIG. 3 , is the signal at the positive input of the ringing peak detector module 400 (and, as shown in the following, of the peak detector circuit 310), while signal SLy, which may for instance correspond to signal SLb inFIG. 3 , is the signal at the negative input. Such input capacitors Cx, Cy allow sustaining the input voltage range, so that it is possible to use a complete CMOS 3.3V architecture. - Then a
module 412 a to select the polarity of the input differential signals SLx, Sly is provided including an arrangement of switches configured to switch upon selection the connections of the feedback signals SLx and SLy to the inputs of a following module, specifically a followingshift module 412 b. - The
shift module 412 b is configured through a respective arrangement of switches to selectively connect the input differential signals SLx, Sly, according to the polarity selected inblock 412 a, to a half voltage Vhd corresponding to the half-dynamic level of the supply voltage, e.g., 1.65 V for 3.3V CMOS. This initialization is needed because theinput buffer 412 is designed to follow the differential variations of the input signal, but is not able to set the DC starting point of the two signals related to GND. - The
input buffer module 412 supplies a shifted differential output formed by a pair of voltage shifted signals, Vs1 and Vs2, where Vs1 indicates the shifted positive signal and Vs2 the shifted negative signal. - In summary, the
input buffer module 412 is configured to supply a buffered differential output, Vs1-Vs2, corresponding to the steady state value ss of the differential input SLx-Sly. - The ringing
peak detector module 400 then includes thepeak detector circuit 310, which receives at its inputs the two signals of the differential output Vs1, Vs2 of theinput buffer module 412, in place of the input differential signals SLx, SLy, and supplies an output voltage Vpout corresponding to the peak of the such buffered differential output Vs1-Vs2. In particular, the positive shifted signal Vs1 is brought to the inverting input of adifferential amplifier 315 while the negative shifted signal Vs2 is brought to a floating ground line FG. The positive input of thedifferential amplifier 315 is connected to the output node Vout of thecircuit 310. Acurrent mirror 316 is connected to the CMOS voltage supply VCC (i.e., is connected between the output of thedifferential amplifier 315 and output node pout), the diode connected transistor of thecurrent mirror 316 receiving the output current of thedifferential amplifier 315 and the output of the other transistor of thecurrent mirror 316 generating the output voltage Vpout. - A peak capacitor Cpeak, to store the peak voltage, is connected between the output node pout and the floating ground line FG.
- The
current mirror 316 charges the peak capacitor Cpeak. When the output is lower than the input theamplifier 315 enables thecurrent mirror 316 to charge the peak capacitor Cpeak. When the output reaches the peak value, theamplifier 315 shuts off thecurrent mirror 316 and the output is held at the peak value, i.e., peak voltage, on the peak capacitor Cpeak. - The
peak detector 310 is a circuit which is known to the person skilled in the art and the peak detector circuit ofFIG. 6 can be substituted with other topologies of peak detector circuits performing corresponding functions. - Then an output voltage Vpout on the output node pout of the
circuit 310 is brought to a differential analog to digital converter (ADC) 418, which receives at its inputs such output voltage Vpout and the positive shifted voltage Vs1. - The
input buffer module 412 is able to keep the steady-state value ss of the differential input, i.e., the difference SLx-SLy, which is stored in the differential shifted output voltage (Vs1−Vs2). - The peak voltage is stored in the differential voltage Vpout−Vs2.
- Therefore, the ringing peak pr, which is the difference between the peak voltage and the steady state ss of the input differential signal, is equal to
-
(Vpout−Vs2)−(Vs1−Vs2)=(Vpout−Vs1) - Using the differential analog to
digital converter 418, it is possible to convert directly the ringing peak signal, as the differential voltage between the output voltage Vpout and the shifted positive input Vs1, without any additional operation. - The output signal of the
differential ADC 418, i.e., the detected ringing peak pr, can be then sent to thesubtraction block 320 to perform a subtraction with the predefined set-point sp, which represents the maximum allowable ringing, in order to obtain a ringing error re to command the gate of the low-side switch SW2. - In the variant embodiment shown in
FIG. 7 , aset point circuit 419 is added to theinput buffer 412. Suchset point circuit 419 includes a set-point store capacitor C2, which is connected at one end at the node on which the negative shifted voltage Vs2 forms and the other is connected through afirst switch 421 to an input receiving the set-point sp and through asecond switch 422 to ground. - Preferably, the capacitance value of the set-point store capacitor C2 is equal to the capacitance value of each of the input capacitors Cx, Cy.
- The
input buffer 412, as inFIG. 6 , is able to keep at its output the steady-state value ss of the differential input SLx−SLy, stored in its differential output voltage Vs1−Vs2. - When the set-point store capacitor C2 is switched from the ground to the set-point sp by operating on the
switches input buffer 412, so that the differential output voltage Vs1−Vs2 of theinput buffer 412 when the set-point store capacitor C2 is switched from the ground to the set-point sp is equal to the sum of the steady-state voltage ss and of the set point sp. - As already indicated, with reference to
FIG. 6 , at the input of thedifferential ADC 418, it is obtained a voltage equal to (Vpout−Vs2)−(Vs1-Vs2); as the difference between Vs1 and Vs2 is equal to the steady-state voltage ss summed to the set-point sp, then at the input of thedifferential ADC 418 it is obtained a voltage which corresponds to the peak voltage of the differential input signal SLx−Sly, minus the steady state of such input signal, SLx−SLy minus the set point sp. More briefly: -
ADC input=peak voltage pv−(steady-state voltage ss+set-point sp) - therefore:
-
ADC input=peak voltage pv−steady-state voltage ss−set-point sp - Since however the ringing peak pr, i.e., the amplitude value of the oscillation, is equal to the difference between the peak voltage pv and the steady-state value ss of the differential input SLx−Sly:
-
(peak voltage pv−steady-state voltage ss)=ringing peak pr - it turns out that at the input of the differential analog to
digital converter 418 it is obtained the differential input: -
pr−sp=re. - In this case therefore the ringing error re can be supplied directly to the
gate driver 200 2 without using thesubtraction block 320. - In other words, the
input buffer 412 is able to maintain the steady state value ss of the input differential signal, since it follows the variations, also very slow variations, of the differential input, in addition to shifting the common mode voltage to the half-dynamic level. - The peak value pv is the peak of the differential signal with respect to the differential zero voltage (Vpout-Vs2). The peak ringing pr is the difference between the peak value pv and the steady state value ss, which can be different from 0V. Peak ringing pr represents the peak of the oscillation that it is desired to reduce. This allows automatically computing the peak ringing pr by directly connecting the voltages Vpout and Vs1 to the analog to
digital converter 418. - The solutions disclosed herein have thus significant advantages with respect to the known solutions.
- The ringing peak detection module by the input buffer is able to maintain the regime value of the differential signal, since it follows the variations, also very slow variation, of the differential input, in addition to shift the common mode voltage to the half-dynamic level.
-
FIG. 8 shows a time diagram of quantities formed in the ringing peak detection module. In the upper diagram, the pair of feedback signals SLx (dotted line) and SLy (dashed line) are represented as a function of time. Between time t1 and t2 the feedback signal SLx presents a sinusoidal wave, i.e., a differential event, between −100 mV and 100 my, while feedback signal SLy is zero and remains equal to zero, i.e., it is connected to the source of a non-switching MOS. The signal SLy is zero, since it is connected to a branch which does not switch. It has to be noted that the circuit described with reference toFIG. 5 , to drive a three-phase motor, is based on the assumption that only one MOS at a time switches. In the example ofFIG. 8 SLx is connected to the branch which is currently switching. - In the central diagram of
FIG. 8 are shown the shifted voltage Vs1 (dotted line) and Vs2 (dashed line). As it can be seen, they have a steady state value at Vhd=1.65V, and, in the time interval t1-t2 corresponding to the differential event they take opposite values with peak to peak amplitude of 100 mV. - In the lower diagram of
FIG. 8 are shown the differential input SLx-SLy (dotted line) and the differential output voltage Vs1−Vs2 (dashed line), which, in the time interval t1-t2 corresponding to the differential event maintain substantially the same values. - The solution here disclosed allows architecture simplification and use of a standard CMOS structure to design the core block.
- Further there is no o need of floating rails to manage a high input swing (common mode).
- On the whole this leads to area saving on the integrated circuit.
- This is obtained in particular by using capacitors to isolate CMOS circuits and using switches to reset the common mode voltage at the half-dynamic level.
- Of course, without prejudice to the principle of the present disclosure, the details of construction and the embodiments may vary widely with respect to what has been described and illustrated herein purely by way of example, without thereby departing from the scope of the present disclosure.
- The solution here described can be applied when a ringing peak detector, able to work at high frequencies, in a voltage range outside standard CMOS operating area, is needed, for instance in BLDC motor drivers.
- The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety, to the extent not inconsistent with the teachings and definitions of the present disclosure. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.
- These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
Claims (20)
1. A ringing peak detector module, comprising:
an input buffer module configured to receive a pair of differential feedback signals on a pair of differential inputs, the pair of differential feedback signals indicating a drain-source voltage of a low-side switch contained in a driver circuit including a full-bridge or half-bridge circuit for driving an inductive electrical load, the input buffer module configured to shift the differential feedback signals so a common mode of the differential feedback signals is at a half-dynamic level of a supply voltage to generate shifted differential voltage signals having a steady-state value of the differential feedback signals, wherein the input buffer module includes a pair of input capacitors, each input capacitor coupled in series with a respective one of the pair of differential inputs;
a ringing peak detector circuit coupled to the input buffer module to receive the shifted differential voltage signals, the ringing peak detector configured generate an output signal corresponding to a peak value of the shifted differential voltage signals;
a differential analog-to-digital converter receiving on a first input one of the shifted differential voltage signals indicating the steady state value of the shifted differential voltage signals plus a maximum value, and receiving on a second input the output signal of the peak detector, and the differential analog-to-digital converter configured to generate a peak ringing digital output signal corresponding to a difference between the output signal and the steady state value plus the maximum value; and
a subtraction circuit coupled to the analog-to-digital circuit to receive the peak ringing digital output signal and configured to generate a ringing error signal to control the driver circuit for driving the inductive electrical load, the ringing error signal being based upon a difference between the digital output signal and the maximum value.
2. The peak detection module according to claim 1 , wherein said input buffer comprises a shift module configured to connect the feedback signals on the differential inputs to a half voltage corresponding to the half-dynamic level of the supply voltage.
3. The peak detection module according to claim 2 , wherein said input buffer includes a polarity module configured to switch the polarity of the feedback signals on the differential inputs.
4. The peak detection module according to claim 3 , wherein said polarity module is coupled to said input capacitors and said shift module is coupled to said polarity module.
5. The peak detection module according to claim 1 , wherein said ringing peak detector circuit comprises:
a peak capacitor;
a differential amplifier receiving on one input one of the shifted differential voltage signals and having an output coupled to the peak capacitor to control a charge of the peak capacitor to store the peak value on the peak capacitor.
6. The peak detection module claim 1 , wherein said ringing peak detector circuit further comprises a current mirror coupled to the output of the differential amplifier and the peak capacitor, the current mirror configured to provide a current to charge the peak capacitor in response to a signal on the output of the differential amplifier.
7. The peak detection module according to claim 1 , wherein said input buffer includes a set point circuit configured to add a voltage corresponding to said maximum value to a differential output voltage of the shifted differential voltage signals generated by of the input buffer module.
8. The peak detection module according to claim 7 , wherein said shifted differential voltage signals generated by the input buffer module include a positive shifted differential voltage signal and a negative shifted differential voltage signal, and wherein the set point circuit includes a set-point storage capacitor coupled at one end to a node of the input buffer module on which the negative shifted differential voltage signal is provided and the is the set-point storage capacitor having a second end coupled through a first switch to an input receiving a voltage corresponding to the maximum value and through a second switch to a reference voltage node, said set point circuit being configured to connect to said set-point storage capacitor to the voltage corresponding to the maximum value to add a voltage corresponding to said maximum value to the differential output voltage of the shifted voltage signals generated by the input buffer so the differential output voltage is equal to the sum of the steady-state voltage of the differential feedback signals and the maximum value.
9. The peak detection module of claim 1 , wherein the maximum value is a predefined maximum value.
10. A system, comprising:
an inductive electrical load driver including a resonant full-bridge or half-bridge circuit having high side electronic switches and low side electronic switches coupled in series between a supply voltage node and a ground node, and having an output node configured to be coupled to an inductive electrical load; and
a peak detection module coupled to the output node for detecting a ringing at the output node of the inductive electric load driver, the peak detection mode including:
first and second input capacitors each having first and second nodes, the first nodes of the first and second input capacitors configured to receive first and second differential feedback signals;
an input buffer configured to receive the first and second differential feedback signals on first and second differential inputs, the first and second differential feedback signals indicating a drain-source voltage of the low side electronic switch contained in the inductive load electrical driver, the input buffer configured to shift the first and second differential feedback signals to provide a common mode of the differential feedback signals at a half-dynamic level of a supply voltage to generate first and second shifted differential voltage signals having a steady-state value of the first and second differential feedback signals;
a ringing peak detector circuit coupled to the input buffer to receive the first and second shifted differential voltage signals, the ringing peak detector configured generate a peak value output signal corresponding to a peak value of the shifted first and second differential voltage signals;
a differential analog-to-digital converter receiving on a first input the first shifted differential voltage signal indicating the steady state value of the first and second shifted differential voltage signals plus a maximum value, and receiving on a second input the peak value output signal of the ringing peak detector circuit, and the differential analog-to-digital converter configured to generate a peak ringing digital output signal corresponding to a difference between the peak value output signal and the steady state value plus the maximum value; and
a subtraction circuit coupled to the analog-to-digital circuit to receive the peak ringing digital output signal and configured to generate a ringing error signal to control the inductive electrical load driver, the ringing error signal being based upon a difference between the digital output signal and the maximum value.
11. The system of claim 10 further comprising a DC motor coupled to the inductive electrical load driver.
12. The system of claim 11 , wherein the inductive electrical load driver is configured to generate pulse width modulation signals to control the DC motor.
13. The system of claim 10 , wherein the high side and low side electronic switches comprise at least one of MOSFET or IGBT transistors.
14. The system of claim 10 , wherein the input buffer comprises:
a shift module configured to connect the first and second differential feedback signals to a half voltage corresponding to the half-dynamic level of the supply voltage; and
a polarity module configured to switch the polarity of the first and second differential feedback signals.
15. The system of claim 14 further comprising a set point circuit coupled to the input buffer, the set point circuit configured to add a voltage corresponding to the maximum value to a differential output voltage of the first and second shifted differential voltage signals.
16. A method, comprising:
receiving first and second differential feedback voltage signals, wherein the first and second differential feedback signals indicate a drain-source voltage of a low-side switch contained in a bridge circuit driving an inductive electrical load;
capacitively coupling the first and second differential feedback voltage signals to first and second input nodes to provide capacitively coupled first and second differential feedback voltage signals on the first and second input nodes;
shifting levels of the capacitively coupled first and second differential feedback voltage signals so a common mode of the capacitively coupled first and second differential feedback voltage signals is equal to a half-dynamic level of a supply voltage and thereby generating shifted first and second differential voltage signals having a steady-state value of the capacitively coupled first and second differential voltage feedback signals;
detecting a peak value of a differential signal formed by the shifted first and second differential voltage signals;
generating a peak ringing output signal corresponding to a difference between detected peak value of the differential signal formed by shifted first and second differential voltage signals and the shifted first differential voltage signal indicating the steady-state value of the shifted first and second differential voltage signals plus the maximum value; and
generating a ringing error signal to control bridge circuit driving the inductive electrical load, the ringing error signal being based upon a difference between the peak ringing output signal and the maximum value.
17. The method of claim 16 , wherein generating the peak ringing output signal comprises performing a differential analog-to-digital conversion of the detected peak value and the shifted first differential voltage signal.
18. The method of claim 16 , wherein generating the peak ringing output signal comprises charging a capacitor to store a voltage corresponding to the peak ringing output signal.
19. The method of claim 16 , wherein generating shifted first and second differential voltage signals having a steady-state value of the capacitively coupled first and second differential voltage feedback signals comprises switching polarities of the capacitively coupled first and second differential feedback voltage signals.
20. The method of claim 16 further comprising generating pulse width modulated controls signals to control the bridge circuit.
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DE102013219167B4 (en) * | 2013-04-26 | 2017-03-02 | Conti Temic Microelectronic Gmbh | Two methods, apparatus and use thereof, each for turning on or off an electronic device |
US9172365B2 (en) * | 2013-08-31 | 2015-10-27 | Freescale Semiconductor, Inc. | Method and circuit for controlling turnoff of a semiconductor switching element |
US9490775B2 (en) * | 2014-12-19 | 2016-11-08 | International Business Machines Corporation | Implementing adaptive control for optimization of pulsed resonant drivers |
US10554875B2 (en) * | 2016-11-21 | 2020-02-04 | Samsung Electro-Mechanics Co., Ltd. | Apparatus for controlling position of camera module using peak detection |
-
2016
- 2016-12-01 IT IT102016000122087A patent/IT201600122087A1/en unknown
-
2017
- 2017-06-14 DE DE102017113143.4A patent/DE102017113143A1/en active Pending
- 2017-06-27 US US15/634,616 patent/US10009018B1/en active Active
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2018
- 2018-06-06 US US16/001,682 patent/US10523189B2/en active Active
Cited By (4)
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US11152885B2 (en) * | 2016-11-18 | 2021-10-19 | Mitsubishi Electric Corporation | Abnormality detection apparatus |
CN112701912A (en) * | 2019-10-23 | 2021-04-23 | 株式会社东芝 | Impact excitation detection circuit and power converter |
US11545893B2 (en) * | 2019-10-23 | 2023-01-03 | Kabushiki Kaisha Toshiba | Electronic circuit and electronic apparatus to output ringing voltage |
CN113098314A (en) * | 2021-04-07 | 2021-07-09 | 清华大学 | IGBT junction temperature monitoring method, device and system |
Also Published As
Publication number | Publication date |
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US10523189B2 (en) | 2019-12-31 |
IT201600122087A1 (en) | 2018-06-01 |
US20180287597A1 (en) | 2018-10-04 |
DE102017113143A1 (en) | 2018-06-07 |
US10009018B1 (en) | 2018-06-26 |
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