AN1625 STMicroelectronics, AN1625 Datasheet
AN1625
Related parts for AN1625
AN1625 Summary of contents
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... VOLTAGE ONE SHOT REGULATOR MONOSTABLE APPLICATION NOTE by Vincenzo Marano PWM current control technique (Syn- OFF V VS BOOT A OCD1 OUT 1 10V V BOOT OCD2 OUT 2 10V SENSE V VS BOOT B OCD3 OUT 3 10V SENSE PWM + MASKING TIME - VREF SENSE COMPARATOR RCOFF D99IN1095B AN1625 A B 1/39 ...
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... AN1625 APPLICATION NOTE 1 INTRODUCTION ................................................................................................................................1 2 DESIGNING AN APPLICATION WITH L6235 ...................................................................................3 2.1 Current Ratings ........................................................................................................................3 2.2 Voltage Ratings and Operating Range ....................................................................................3 2.3 Choosing the Bulk Capacitor....................................................................................................5 2.4 Layout Considerations .............................................................................................................5 2.5 Sensing Resistor ......................................................................................................................7 2.6 Charge pump external components .........................................................................................8 2.7 Sharing the Charge Pump Circuitry .........................................................................................9 2.8 Reference Voltage for PWM Current Control.........................................................................10 2.9 Input Logic pins ......................................................................................................................11 2 ...
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... S and V because the bootstrap voltage ( The output pin sees a similar behavior, but with a slightly larger SENSE AN1625 APPLICATION NOTE prevent working into S ringings. It should be noted, however, that S is less than 10V DS(ON) supply. This supply is ...
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... AN1625 APPLICATION NOTE sees a voltage above V , due to voltage drop across the high-side (integrated) freewheeling diode, as the cur- S rent reverses direction and flows into the bulk capacitor. It turns out that the highest differential voltage is ob- served between two OUT pins when a phase change turns a high-side off during an off-time, and this must always be kept below 60 V [2] ...
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... I ESR the capacitor ESR should be lower than OUT 0.5V ESR ------------ 250m = 2 A PCB tracks (see Voltage Ratings and Operating S pins of the device is subject to higher peaks due to reverse recovery SB AN1625 APPLICATION NOTE ). The r.m.s. value of the current flowing 5/39 ...
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... AN1625 APPLICATION NOTE Figure 5. Typical Application and Layout suggestions. + µC Logic Supply or 3.3 ÷ Custom Logic - ÷1V ref High current GND tracks (i.e. the tracks connected to the sensing resistor) must be connected directly to the neg- ative terminal of the bulk capacitor. A good quality, high-frequency bypass capacitor is also required (typically a 100 nF÷ ...
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... GND pins (see Figure 5) must be taken as short as possible rms S ENSE is the r.m.s. value of the load current. rms ENSE AN1625 APPLICATION NOTE DON’T put a diode here! spike that can destroy the IC ÷ must be avoided. SENSE ; D , SENSE 7/39 ...
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... AN1625 APPLICATION NOTE duce the inductance. R tolerance reflects on the peak current error: 1% resistors should be preferred. SENSE The following table shows R SENSE examples of current peak values 0.5 1 1.5 2 2.6 Charge pump external components An internal oscillator, with its output at CP pin, switches from GND with a typical frequency of 600 kHz (see Figure 7) ...
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... Figure 8. Sharing the charge pump circuitry. To other Devices V BOOT To High-Side Gate Drivers for the high side DMOS, so higher dissipating power. DS(ON) C18 = 100 L6235 AN1625 APPLICATION NOTE pin of each device. BOOT D2 = BAT47 D1 = BAT47 C8 = 100nF C5 = 33nF BOOT High-Side ...
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... AN1625 APPLICATION NOTE 2.8 Reference Voltage for PWM Current Control The device has an analog input, Vref, connected to the internal sense comparator, to control the peak value of the motor current through the integrated PWM circuitry. A fixed reference voltage can be easily obtained through a resistive divider from an available 5 V voltage rail (maybe the one supplying the µC or the rest of the applica- tion) and GND. A very simple way to obtain a variable voltage without using a DAC is to low-pass filter a PWM output of a µ ...
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... Over Current Pro- tection section). Figure 11. DIAG pin. = 1.3 V. Pins are ESD protected (see Figure 10) (2kV human-body TH(OFF FWD/REV , BRAKE , ENABLE ESD Protection µC or Logic Output EN R1 DIAG C1 AN1625 APPLICATION NOTE 11/39 ...
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... AN1625 APPLICATION NOTE 2.11 Programmable off-time Monostable The L6235 includes a constant off time PWM Current Controller. The current control circuit senses the bridge current by sensing the voltage drop across an external sense resistor connected between the source of the three lower power MOS transistors and ground, as shown in Figure 12. As the current in the motor increases the voltage across the sense resistor increases proportionally ...
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... OFF OFF implement the drive circuit for most motors. OFF also affects the Rise Time t OFF , which depends by motors and supply parameters, has ON(MIN) AN1625 APPLICATION NOTE OFF BLANK Slow Decay t RCRISE t RCFALL ...
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... AN1625 APPLICATION NOTE 1.5 s (typ. value MIN – RCRISE DT 600 · C RCRISE OFF 2.11.1 Off-time Selection and minimum on-time Figure 14 also shows the lower limit for the On Time t has to be said that t is always bigger than t ...
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... Figure 16. Minimum on-time can cause the PWM controller to loose the regulation DEAD TIME C) SYNCHRONOUS RECTIFICATION = V × where LOAD ref SENSE AN1625 APPLICATION NOTE DEAD TIME / ( the duty-cycle and OFF minimum about 1.5 µs needed less than 1.5 µ ...
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... AN1625 APPLICATION NOTE 2.12 Over Current Detection To implement an Over Current (i.e. short circuit) Protection, a dedicated Over Current Detection (OCD) circuitry (see Figure 17 for a simplified schematic) senses the current in each high side. Power DMOS are actually made up with thousands of individual identical cells, each carrying a fraction of the total current flowing. The current sensing element, connected in parallel to the Power DMOS, is made only with few such cells, having a 1:N ratio compared to the power DMOS ...
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... DELAY DELAY DIS ABLE OCD RISE ------------------------------------------- - = RISE DD AN1625 APPLICATION NOTE t DISABLE Output Current t D(ON) DIAG TH(ON) V EN(LOW) t EN(RISE The current begins to D(OFF)EN ), switches the internal OCD(OFF ensure a safe r.m.s. value DISABLE . – ...
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... AN1625 APPLICATION NOTE The total intervention time is where OCD(OFF) OCD(ON) D(ON)EN D(OFF)EN applied The external RC network particular, must be chosen obtaining a reasonable fast OCD intervention (short and a safe disable time (long t DELAY at least 100µs for t are recommended, keeping the delay time below 1÷2µs at the same time. ...
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... AN1625 APPLICATION NOTE . 19/39 ...
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... AN1625 APPLICATION NOTE 2.13 Power Management Even when operating at current levels well below the maximum ratings of the device, the operating junction tem- perature must be kept below 125 °C. Figure 20 shows the IC dissipated power versus the r.m.s. load current different driving sequences, assum- ing the supply voltage is 24V ...
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... PCB [3]. The model considers power dissipation during the on-time and the off-time, taking into account the selected de- cay, rise and fall time (when a phase change occurs), the switching losses and the quiescent current power dis- sipation. AN1625 APPLICATION NOTE 21/39 ...
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... AN1625 APPLICATION NOTE Figure 22. Current in the three phases and the signal of one of the hall effect sensors. Hall Figure 23. Input Data. Maximum Drain-Source ON Resistance Max imum diode voltage Quiescent Current Maximum BEMF Voltage Motor Inductance Motor Resistance Polar Couples Supply Voltage ...
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... Ipk [ Tfall T Lm Ipk Rm + Ipk [W] (2Ron · Irms [W] (2Vs · I · Tcom · Tload · fSW [W] [ Pcom + Pload + Pfall + Prise AN1625 APPLICATION NOTE Vs / (250V/ s) n*sp/ – + --------------------------------------------- - – ---------------------------- – ...
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... AN1625 APPLICATION NOTE Figure 25. Thermal Data inputs and results Package Copper Area Copper Area is on Ground Layer Ambient Temperature Thermal Resistance Junction to Ambient Thermal Resistance Junction to Pins / Slug Estimated Junction Temperature Estimated Pins / Slug Temperature 2.14 The decoding logic The L6235 integrated decoding logic provides the correct sequence on the three outputs for motors with both 60° ...
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... Tacho monostable is identical to RCoff monostable, and the fixed pulse time is defined by: Figure 27. tacho pulses selection pin. PULSE to the Decoding Logic Tacho Monostable t 0. uls e PULSE PULS 47k PUL 3 = 20k R PUL 100 Cpul [nF] AN1625 APPLICATION NOTE 100k PUL 100 ) set by PULSE PULSE 25/39 ...
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... AN1625 APPLICATION NOTE Also the duty cycle of this signal, so its average value is proportional to the motor rotation speed. Simply inte- grating the square-wave a voltage proportional to the motor speed will be available to realize a speed loop Figure 28: R and C PULSE PULSE to a voltage proportional to the desired speed (V speed error signal ...
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... ---------------------------------------------------------------------- loop <v > Op-Amp I [ pullup pulse [rad/ are shown in Figure 30. loop AN1625 APPLICATION NOTE G k – <v > [V] ref 1 2 SENSE [Nm motor ...
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... AN1625 APPLICATION NOTE Figure 30. G module and phase. loop 135 180 The relation between the speed reference voltage ( given by the expression: M for a given speed, the speed reference voltage to apply is: Designing the speed loop, care must be taken choosing the values good compromise between static performance, dynamic performance, stability and torque ripple: 2 ...
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... amp – ------------------------ - ----------------------------------------------------------------------------------------------------------- s spe – AN1625 APPLICATION NOTE 0 2 Vref=4. 0.01 0.02 0.005 0.015 Resistant Torque (Tb) [Nm – amp – amp – ...
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... AN1625 APPLICATION NOTE Figure 32. Speed response to a 1mNm resistant torque step 100 0 Figure 33. Speed response speed voltage step. 8000 6400 4800 3200 1600 0 0 2.15.3 Loop Stability: The phase margin is defined as 180° minus the phase of Gloop at the cut frequency (where Gloop=1). It should be at least 45° ...
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... BEMF is less than the supply voltage there is no braking effect (since the freewheeling diodes cannot be turned on) until the disable time ex- pires and all the high side PowerDMOS turn on again AN1625 APPLICATION NOTE function, and a ripple in the ref- oop ...
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... AN1625 APPLICATION NOTE Figure 34. Overcurrent during motor braking. on-time Figure 35. Overcurrent during motor braking. 3 APPLICATION EXAMPLE Application Data Rotation Speed: Winding peak Current: Maximum Ripple: Maximum BEMF at 10000rpm: 32/39 braking I “Brake” Command EN = DIAG 10000 rpm (f =167Hz) EL 1.5 A 350mA 10 V overcurrent – disable time ...
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... OFF ref 470 pF Ceramic 47nF Ceramic copper area on the PCB, a ground layer and a PowerSO36 package, the AN1625 APPLICATION NOTE 320 mA. resistor to reduce EMI). 7 the EN pin a 5.6 nF has been OFF 1N4148 220nF 35V Ceramic Ceramic 100µF 50V ESR<200m ...
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... AN1625 APPLICATION NOTE 4 APPENDIX - EVALUATION BOARDS 4.1 PractiSPIN PractiSPIN is an evaluation and demonstration system that can be used with the PowerSPIN family (L62XX) of devices. A Graphical User Interface (GUI) (see Figure 37) program runs on an IBM-PC under windows and com- municates with a common ST7 based interface board (see Figure 38) through the RS232 serial port. The ST7 interface board connects to a device specific evaluation board (target board) via a standard 34 pin ribbon cable interface ...
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... C board. Running the evaluation board in stand-alone mode, instead, four switches (S1) allow enabling the device, set- ting the direction of the rotation, braking the motor, choosing to run in torque or speed mode. R17 and R22 set AN1625 APPLICATION NOTE JP1, JP2 2-pin jumper R1 700 0 ...
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... AN1625 APPLICATION NOTE the reference voltage provided to the Vref pin of the L6235 (in torque mode the error amplifier, U2 (in speed mode); R20, C11 make up a low-pass filters to provide an external reference voltage by a PWM output (see also the Reference Voltage section). R10, C8 are used to set the off-time and R11, C9 set the duration of the TACHO output pulses ...
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... VCP TACHO 15 4 VBOOT RCOFF 19 13 GND VREF 18 GND 7 GND 6 2 GND DIAG PullUp R6 DIAG AN1625 APPLICATION NOTE TP U2B LM358 8 4 +5V CN4 VREF R14 C10 4 R13 R16 R12 R11 R18 C9 R10 R15 Pullup C8 R17 PullUp C7 H1H2H3 VREF ...
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... AN1625 APPLICATION NOTE Figure 41. L6235 Evaluation Board Component placement. Figure 42. L6235 Evaluation Board Top Layer Layout. Signal GND 38/39 Power GND Bulk Capacitor ...
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