TD340ID STMicroelectronics, TD340ID Datasheet - Page 11

• Manufacturer Part Number: TD340ID
• Description: MOSFET & Power Driver ICs H-Bridge Quad MOSFET
• Manufacturer: STMicroelectronics
• Type: High Side/Low Sider

Specifications of TD340ID

• Supply Voltage (min): 6.5 V
• Supply Current: 7 mA
• Maximum Power Dissipation: 500 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: SO-20
• Bridge Type: H Bridge
• Minimum Operating Temperature: - 40 C
• Number Of Drivers: 4
• Number Of Outputs: 4
• Output Current: 1.5 A
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

TD340
Reversed battery active protection
In full H-bridge configuration, there is a risk in case of power voltage reversal due to the intrinsic diodes
inside the MOS. A passive protection solution is to wire a diode between the H-bridge and the power
supply. Disadvantages are voltage drop and power dissipation.
The TD340 provides support for reversed battery active protection.
An oscillator OSC output is available to allow proper command of a 5th MOS connected upside down.
The MOS must have low threshold voltage because the oscillator output swing is about 6.5V.
In normal conditions, the MOS intrinsic diode supplies power to the driver at startup. When the TD340 is
started, the OSC output enables the MOS to switch on, providing lower voltage drop and lower power
dissipation.
In case of reversed battery, the 5th MOS remains off, and no dangerous voltages can reach the driver nor
the power MOS.
The OSC oscillator can only supply a few mA. It must be loaded with a large impedance, typically 100pF
and 680k.
Figure 5 : Reversed Battery Active Protection Principle
UVLO and OVLO protections
The TD340 includes protections again overvoltage and undervoltage conditions.
Overvoltage is dangerous for the MOS and for the load due to possible excessive currents and power
dissipation.
Undervoltage is dangerous because MOS driving is no more reliable. MOS could be in linear mode with
high ohmic dissipation.
TD340 Under Voltage LockOut and Over Voltage LockOut features protect the system from no
operational power voltage. UVLO and OVLO thresholds are 6.2V and 20V. Hysteresis provides reliable
behavior near the thresholds.
During UVLO and OVLO, MOS are switched off (TD340 in disable state).
Osc
Normal Conditions
TD340
Vbatt
1
2
3
4
Vbatt+6V
M
~Vbatt
GND
VBATT
2
3
ALL MOSFETS AND DRIVER ARE PROTECTED
REVERSED BATTERY
Osc
TD340
Driver is not supplied
Vbatt
1
2
3
4
5
M
GND
VBATT
MOSFET 5
REMAINS
OFF
2
3
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