L6229Q DMOS driver for three-phase brushless DC motor Features ■ Operating supply voltage from 8 to 52 V ■ 2.8 A output peak current (1.4 A RMS) ■ RDS(on) 0.73 Ω typ.
Contents L6229Q Contents 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3 Thermal data . . . . . . . . . . . . . . . . . .
L6229Q 1 Block diagram Block diagram Figure 1.
Electrical data L6229Q 2 Electrical data 2.1 Absolute maximum ratings Table 2. Absolute maximum ratings Symbol Parameter VS VOD VBOOT Parameter Value Unit Supply voltage VSA = VSB = VS 60 V Differential voltage between: VSA, OUT1, OUT2, SENSEA and VSB, OUT3, SENSEB VSA = VSB = VS = 60 V; VSENSEA = VSENSEB = GND 60 V Bootstrap peak voltage VSA = VSB = VS VS + 10 V VIN, VEN Logic inputs voltage range -0.3 to +7 V VREF Voltage range at pin VREF -0.
L6229Q 2.3 Electrical data Thermal data Table 4. Symbol Rth(JA) Thermal data Parameter Thermal resistance junction-ambient max. (1) Value Unit 42 °C/W 2 1. Mounted on a double-layer FR4 PCB with a dissipating copper surface of 0.5 cm on the top side plus 6 cm2 ground layer connected through 18 via holes (9 below the IC).
Pin connection Pin connection OUT1 RCOFF SENSEA DIAG H1 H3 H2 Pin connection (top view) 32 31 30 29 28 27 26 25 23 OUT2 NC 3 22 VSA NC 4 21 GND NC 5 20 VSB NC 6 19 OUT3 NC 7 18 NC NC 8 17 VBOOT TACHO 9 Note: 6/28 10 11 12 13 14 15 16 BRAKE 2 VREF NC EN VCP FW/REW 24 SENSEB 1 RCPULSE GND NC Figure 2. NC 3 L6229Q 1 The pins 2 to 8 are connected to die PAD. 2 The die PAD must be connected to GND pin.
L6229Q Table 5. Pin connection Pin description N° Pin Type Function 1, 21 GND GND 9 TACHO Open drain output Frequency-to-voltage open drain output. Every pulse from pin H1 is shaped as a fixed and adjustable length pulse. 11 RCPULSE RC pin RC network pin. A parallel RC network connected between this pin and ground sets the duration of the monostable pulse used for the frequency-tovoltage converter. 12 SENSEB 13 FWD/REV Logic input Selects the direction of the rotation.
Electrical characteristics L6229Q 4 Electrical characteristics Table 6. Electrical characteristics (VS = 48 V, TA = 25 °C, unless otherwise specified) Symbol Parameter Test condition Min Typ Max Unit VSth(ON) Turn-on threshold 5.8 6.3 6.8 V VSth(OFF) Turn-off threshold 5 5.
L6229Q Table 6. Electrical characteristics Electrical characteristics (continued) (VS = 48 V, TA = 25 °C, unless otherwise specified) Symbol fCP Parameter Test condition Charge pump frequency TJ = -25 °C to 125 °C Min (1) Typ Max Unit 0.6 1 MHz PWM comparator and monostable IRCOFF VOFFSET Source current at pin RCOFF Offset voltage on sense comparator (4) tprop Turn OFF propagation delay tblank Internal blanking time on sense comparator tON(min) VRCOFF = 2.5 V (3) 3.5 5.
Electrical characteristics Figure 3. L6229Q Switching characteristic definition EN Vth(ON) Vth(OFF) t IOUT 90% 10% t D01IN1316 tD(OFF)EN Figure 4.
L6229Q Circuit description 5 Circuit description 5.1 Power stages and charge pump The L6229Q integrates a three-phase bridge, which consists of 6 power MOSFETs connected as shown on the block diagram (see Figure 1). each power MOS has an RDS(ON) = 0.73 Ω (typical value @ 25 °C) with intrinsic fast freewheeling diode. Switching patterns are generated by the PWM current controller and the hall effect sensor decoding logic (see relative paragraph 3.3 and 3.5).
Circuit description 5.2 L6229Q Logic inputs Pins FWD/REV, BRAKE, EN, H1, H2 and H3 are TTL/CMOS and microcontroller compatible logic inputs. The internal structure is shown in Figure 6. Typical value for turn-on and turn-off thresholds are respectively Vth(ON)= 1.8 V and Vth(OFF)= 1.3 V. Pin EN (Enable) has identical input structure with the exception that the drain of the Overcurrent and thermal protection MOSFET is also connected to this pin.
L6229Q 5.3 Circuit description PWM current control The L6229Q 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 9. As the current in the motor increases the voltage across the sense resistor increases proportionally.
Circuit description L6229Q Figure 10. Output current regulation waveforms IOUT VREF RSENSE tON tOFF tOFF 1μs tBLANK VSENSE 1μs tBLANK VREF Slow Decay 0 Slow Decay tRCRISE VRC tRCRISE 5V 2.5V tRCFALL tRCFALL 1μs tDT 1μs tDT ON OFF SYNCHRONOUS RECTIFICATION B D02IN1351 C D A B C D Figure 11 shows the magnitude of the Off Time tOFF versus COFF and ROFF values. It can be approximately calculated from the equations: tRCFALL = 0.6 · ROFF · COFF tOFF = tRCFALL + tDT = 0.
L6229Q Circuit description ⎧ t ON > t ON ( MIN ) = 2.5μs ⎫ ⎨ ⎬ ⎩ t ON > t RCRISE – t DT ⎭ (typ. value) tRCRISE = 600 · COFF Figure 12 shows the lower limit for the on time tON for having a good PWM current regulation capacity. It has to be said that tON is always bigger than tON(MIN) because the device imposes this condition, but it can be smaller than tRCRISE - tDT. In this last case the device continues to work but the off time tOFF is not more constant.
Circuit description 5.4 L6229Q Slow decay mode Figure 13 shows the operation of the bridge in the slow decay mode during the off time. At any time only two legs of the three-phase bridge are active, therefore only the two active legs of the bridge are shown in the figure and the third leg will be off. At the start of the Off Time, the lower power MOS is switched off and the current recirculates around the upper half of the bridge. Since the voltage across the coil is low, the current decays slowly.
L6229Q Circuit description and the 120 codes it is possible to drive the motor with all the four conventions by changing the direction set. Table 8.
Circuit description 5.6 L6229Q Tacho A tachometer function consists of a monostable, with constant off time (tPULSE), whose input is one hall effect signal (H1). It allows developing an easy speed control loop by using an external op amp, as shown in Figure 17. For component values refer to Application Information section. The monostable output drives an open drain output pin (TACHO).
L6229Q Circuit description Figure 17. Tachometer speed control loop H1 RCPULSE TACHO MONOSTABLE VDD RPUL CPUL RDD R3 TACHO C1 R4 VREF R1 VREF CREF2 CREF1 R2 Figure 18. tPULSE versus CPUL and RPUL 4 1 .10 R PUL = 100kΩ R PUL = 47kΩ 3 1 .
Circuit description 5.7 L6229Q Non-dissipative overcurrent detection and protection The L6229Q integrates an overcurrent detection circuit (OCD) for full protection. This circuit provides output-to-output and output-to-ground short circuit protection as well. With this internal over current detection, the external current sense resistor normally used and its associated power dissipation are eliminated. Figure 19 shows a simplified schematic for the overcurrent detection circuit.
L6229Q Circuit description Figure 20. Overcurrent protection waveforms IOUT ISOVER VEN=VDIAG VDD Vth(ON) Vth(OFF) VEN(LOW) ON OCD OFF ON tDELAY BRIDGE tDISABLE OFF tOCD(ON) tEN(FALL) tOCD(OFF) tEN(RISE) tD(ON)EN tD(OFF)EN D02IN1383 Figure 21. tDISABLE versus CEN and REN R EN = 220 kΩ 3 1 .1 0 R EN = 100 kΩ R EN = 47 kΩ R EN = 33 kΩ tDISABLE [µs] R EN = 10 kΩ 100 10 1 1 10 100 C E N [n F ] Figure 22. tDELAY versus CEN. tdelay [μs] 10 1 0.
Application information 6 L6229Q Application information A typical application using L6229Q is shown in Figure 23. Typical component values for the application are shown in Table 9. A high quality ceramic capacitor (C2) in the range of 100 nF to 200 nF should be placed between the power pins VSA and VSB and ground near the L6229Q to improve the high frequency filtering on the power supply and reduce high frequency transients generated by the switching.
L6229Q Application information Figure 23. Typical application to SENSEB to EN H1 H3 H2 32 31 30 29 28 27 26 25 NC RCOFF SENSEA DIAG H1 H3 H2 COFF OUT1 ROFF Cp 1 GND VCP 24 2 NC 3 NC VSA 22 4 NC GND 21 5 NC VSB 20 6 NC OUT3 19 7 NC NC 18 8 NC OUT2 23 EN VREF BRAKE 9 10 11 12 13 14 15 16 CPUL RPUL D2 + C1 _ SIGNAL GROUND VBOOT 17 VREF R1 CREF1 CREF1 R2 C3 R4 REN CEN 6.
Application information 6.2 L6229Q Thermal management In most applications the power dissipation in the IC is the main factor that sets the maximum current that can be delivered by the device in a safe operating condition. Therefore, it has to be taken into account very carefully. Besides the available space on the PCB, the right package should be chosen considering the power dissipation. Heat sinking can be achieved using copper on the PCB with proper area and thickness.
L6229Q 7 Package mechanical data Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Table 10. VFQFPN 5 x 5 x 1.0, 32 lead, pitch 0.50 Databook (mm) Dim. Min Typ Max A 0.80 0.85 0.95 b 0.18 0.25 0.30 b1 0.165 0.175 0.185 D 4.85 5.
Package mechanical data L6229Q Figure 25.
L6229Q 8 Revision history Revision history Table 11.
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