ST L6234 User Manual

L6234

Three phase motor driver

Features

■Supply voltage from 7 to 52 V

■5 A peak current

■RDSon 0.3 Ω typ. value at 25 °C

■Cross conduction protection

■TTL compatible driver

■Operating frequency up to 150 kHz

■Thermal shutdown

■Intrinsic fast free wheeling diodes

■Input and enable function for each half bridge

■10 V external reference available

Description

The L6234 is a triple half bridge to drive a brushless DC motor.

It is realized in BCDmultipower technology which combines isolated DMOS power transistors with CMOS and Bipolar circuits on the same chip.

By using mixed technology it has been possible to optimize the logic circuitry and the power stage to achieve the best possible performance.

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The output DMOS transistors can sustain a very high current due to the fact that the DMOS structure is not affected by the second breakdown effect, the RMS maximum current is practically limited by the dissipation capability of the package.

All the logic inputs are TTL, CMOS and µP compatible. Each channel is controlled by two separate logic input.

L6234 is available in 20 pin PowerDIP package (16+2+2) and in PowerSO20.

Table 1.	Device summary
	Order code	Package	Packing
	L6234	PowerDIP20	Tube
	L6234PD	PowerSO20	Tube
	L6234PD013TR	PowerSO20	Tape and reel

November 2011

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Contents	L6234

Contents

1	Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 3
2	Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. 4
3	Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
4	Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		6
	4.1	Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
5	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		7
6	Circuit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		8
7	Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		9
8	Mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		12
9	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		15

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L6234	Block diagram

1 Block diagram

Figure 1. Block diagram

			Μ)
Q)	Μ)
9&3	95()	9%227	1
&+$5*(		95()
3803		9
		9V		Μ)
,1		WR 9
		7+	Μ)
		287
(1		7/
,1		7+
		287
(1		7/
7+(50$/		6(16(
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,1		7+
		287
(1		7/
		6(16(
		*1'	56(16(
		' ,1$
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Pin connections	L6234

2 Pin connections

Figure 2. Pin connections

	287				287		*1'			*1'
	,1				,1		6(16(			6(16(
	(1				(1		(1			9%227
	96				6(16(		,1			9&3
	*1'				*1'		287			95()
	*1'				*1'		287			287
	96				6(16(		,1			,1
							(1			(1
	(1				9%227
							96			96
	,1				9&3
							*1'			*1'
	287					95()

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	Table 2.	Pin functions
	PowerDIP	PowerSO20	Name	Function
	1	6	OUT 1
	20	5	OUT 2	Output of the channels 1/2/3.
	10	15	OUT 3
	2	7	IN 1	Logic input of channels 1/2/3. A logic HIGH level (when the
				corresponding EN pin is HIGH) switches ON the upper DMOS
	19	4	IN 2
				Power Transistor, while a logic LOW switches ON the
	9	14	IN 3
				corresponding low side DMOS Power.
	3	8	EN 1	Enable of the channels 1/2/3. A logic LOW level on this pin
	18	3	EN 2
				switches off both power DMOS of the related channel.
	8	13	EN 3
	4,7	9, 12	Vs	Power supply voltage.
	14	19	SENSE2	A sense resistor connected to this pin provides feedback for
				motor current control for the bridge 3.
	17	2	SENSE1	A sense resistor connected to this pin provides feedback for
				motor current control for the bridges 1 and 2.
				Internal voltage reference. A capacitor connected from this pin
	11	16	VREF	to GND increases the stability of the Power DMOS drive
				circuit.
	12	17	VCP	Bootstrap oscillator. Oscillator output for the external charge
				pump.
	13	18	VBOOT	Overvoltage input to drive the upper DMOS
	5,6	1,10	GND	Common ground terminal. In PowerDIP and SO packages
	15,16	11,20		these pins are used to dissipate the heat forward the PCB.

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L6234	Thermal data

3 Thermal data

	Table 3.	Thermal data
	Symbol	Parameter	DIP16+2+2	PowerSO20	Unit
	R	Thermal resistance, junction to pin	12 (1)	–	°C/W
	th j-pin
	R	Thermal resistance, junction to ambient	40 (2)	–	°C/W
	th j-amb1
	R	Thermal resistance, junction characteristics) to	50 (3)	–	°C/W
		ambient
	th j-amb2
	Rth j-case	Thermal resistance junction-case	–	1.5	°C/W

1.The thermal resistance is referred to the thermal path from the dissipating region on the top surface of the silicon chip, to the points along the four central pins of the package, at a distance of 1.5 mm away from the stand-offs.

2.If a dissipating surface, thick at least 35 mm, and with a surface similar or bigger than the one shown in Figure 3, is created making use of the printed circuit. Such heatsinking surface is considered on the bottom side of an horizontal PCB (worst case).

3.If the power dissipating pins (the four central ones), as well as the others, have a minimum thermal connection with the external world (very thin strips only) so that the dissipation takes place through still air and through the PCB itself. It is the same situation of note 2, without any heatsinking surface created on purpose on the board.

Figure 3. Printed Heatsink

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