BridgeSwitch
Family
High-Voltage, Self-Powered, Half-bridge Motor Driver with
Integrated Device Protection and System Monitoring
Product Highlights
Highest Performance and Design Flexibility
•
Fully integrated half-bridge stage with up to 98% efficiency
• Eliminates external heat sink at rated continuous RMS current
• 600 V N-channel power FREDFETs
• Ultra-soft, fast recovery diode
• Accurate instantaneous phase current information output (BRD126X)
•
Eliminates external sensing and amplification circuitry
• Self-biased low-side and high-side drivers
• Eliminates need for auxiliary power supply
• Small footprint surface mount inSOP-24C package
• Exposed pads enable heat sinking through PCB
• Controlled FREDFET switching speed reduces EMI
• Adustable cycle-by-cycle current limit for both FREDFETs
• Fail-safe operation
• Internal dual level thermal overload protection
•
Self-configuring system level monitoring input
• Four level DC bus undervoltage
• DC bus overvoltage
• System temperature
• Adaptive dead time
• Simultaneous conduction lockout protection
• Bi-directional bussed open Drain single wire interface
• Reports status updates to system MCU
• Successful power-up
• Internal over-current or temperature faults
• System level faults
•
Includes device identification
• Status query through system MCU
• Device fault reset through system MCU
HV+
HD
V
DD
BPH
HS
Drive
XH
System
MCU
SM
FAULT
/INH
INL
IPH
BPL
HB
LS
Drive
&
Control
BridgeSwitch
ID
SG
XL
LS
Enhanced Safety and Reliability Features
HV-
PI-8314-100518
Figure 1.
Typical 3-Phase Inverter Schematic (BRD126X).
Status Interface
Br
Sw
idge
itch
TM
Figure 2.
InSOP-24C Package (Top and Bottom Sides).
Product Family
Product
3
BRD1160C /
BRD1260C
BRD1161C /
BRD1261C
BRD1163C /
BRD1263C
BRD1165C /
BRD1265C
DC Output
Current
1
1.0 A
1.7 A
3.0 A
5.5 A
Continuous
RMS Current
2
0.22 A
0.50 A
0.75 A
1.00 A
Applications
• 2- or 3-phase high-voltage PM and BLDC motor drives
• Up to 300 W typical inverter output power
• Appliances including dish washers and refrigerators
•
Condenser fans in high efficiency air conditioners
Description
The BridgeSwitch™ family of integrated half-bridges dramatically
simplifies the development and production of high-voltage inverter
driven 2- or 3-phase PM or BLDC motor drives. It incorporates two
high-voltage N-channel power FREDFETs with low and high-side drivers
in a single small-outline package. The internal power FREDFETs offer
ultra-soft and ultrafast diodes ideally suited for hard switched inverter
drives. Both drivers are self-supplied eliminating the need for an
external auxiliary power supply. BridgeSwitch provides a unique
instantaneous phase current output signal simplifying implementation of
sensor-less control schemes. The low-profile, compact footprint surface
mount package offers extended creepage distances and allows heat
sinking of both power FREDFETs through the printed circuit board.
BridgeSwitch offers internal fault protection functions and external
system level monitoring. Internal fault protection includes cycle-by-
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Table 1. Product Family.
Notes:
1. Continuous DC output current per FREDFET, calculated at 25 °C case and
125 °C junction temperature. Normally limited by internal circuitry
2. Continuous phase RMS current, internal self-supply, 340 V bus, trapezoidal
commutation with 12 kHz high-side PWM, PCB heat sinking with 50 °C case
temperature rise.
3. Package: InSOP-24C.
cycle current limit for both FREDFETs and two level thermal overload
protection. External system level monitoring includes DC bus sensing
with four undervoltage levels and one overvoltage level as well as
driving external sensors such as an NTC. The bi-directional bussed
single wire status interface reports observed status changes.
November 2018
This Product is Covered by Patents and/or Pending Patent Applications.
BridgeSwitch
BPH
REGULATOR
14.5 V
HD
DIGITAL
PROCESS FOR
TESTING AND
TRIM
ANALOG BUILDING BLOCK:
VOLTAGE SUPPLY, REFERENCE VOLTAGE,
REFERENCE CURRENT, CLK
HS SYSTEM
COMMUNICATION
XH
CURRENT LIMIT
PROGRAM
SenseFET
GATE LOGIC
CURRENT
LIMIT
HS RECEIVER
DRIVER
I
SNS
Power
FREDFET
HB
BPL
INH
INL
INH/INL
CONTROL
ANALOG BUILDING BLOCK:
VOLTAGE SUPPLY, REFERENCE VOLTAGE,
REFERENCE CURRENT, CLK
ID
CHIP
CONFIGURATION
DIGITAL
LOGIC
COMMUNICATION
FAULT
FAULT
SM
LINE AND
TEMPERATURE
MONITOR
XL
CURRENT LIMIT
PROGRAM
CURRENT
LIMIT
SenseFET
GATE LOGIC
DRIVER
I
SNS
Power
FREDFET
SG
LS
PI-8296a-120117
Figure 3.
Functional Block Diagram BRD116X.
2
Rev. F 11/18
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BridgeSwitch
BPH
REGULATOR
14.5 V
HD
DIGITAL
PROCESS FOR
TESTING AND
TRIM
ANALOG BUILDING BLOCK:
VOLTAGE SUPPLY, REFERENCE VOLTAGE,
REFERENCE CURRENT, CLK
HS SYSTEM
COMMUNICATION
XH
CURRENT LIMIT
PROGRAM
SenseFET
GATE LOGIC
CURRENT
LIMIT
HS RECEIVER
DRIVER
I
SNS
Power
FREDFET
HB
BPL
INH
INL
INH/INL
CONTROL
ANALOG BUILDING BLOCK:
VOLTAGE SUPPLY, REFERENCE VOLTAGE,
REFERENCE CURRENT, CLK
ID
FAULT
CHIP
CONFIGURATION
DIGITAL
LOGIC
COMMUNICATION
FAULT
GAIN
IPH
SM
LINE AND
TEMPERATURE
MONITOR
XL
CURRENT LIMIT
PROGRAM
CURRENT
LIMIT
SenseFET
GATE LOGIC
DRIVER
I
SNS
Power
FREDFET
SG
LS
PI-8296-091917
Figure 4.
Functional Block Diagram BRD126X.
3
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Rev. F 11/18
BridgeSwitch
Pin Functional Description
HIGH-SIDE DRAIN (HD) Exposed Pad
The HD exposed pad is the electrical connection to the high-side
power FREDFET Drain connection. It is also the input for the internal
low-side and high-side self-supply circuitry.
EXTERNAL CURRENT LIMIT LOW-SIDE (XL) Pin (Pin 1)
This pin connects to a resistor to set the cycle-by-cycle current limit
for the low-side power FREDFET.
PHASE CURRENT OUTPUT (IPH) Pin (Pin 2, BRD126X)
This pin connects to a small signal resistor and provides low-side
FREDFET Drain current information. The pin should be left floating if
the function is not used. Function is not available with BRD116X.
SIGNAL GROUND (SG) Pin (Pins 3 and 10)
These pins are the ground reference connection for low-side
controller small signal pins and the system micro-controller.
BYPASS LOW-SIDE (BPL) Pin (Pin 4)
This pin connects to the external bypass capacitor for the low-side
controller and FREDFET Gate driver.
CONTROL INPUT LOW-SIDE (INL) Pin (Pin 5)
Active high logic level control input for the low-side power FREDFET.
CONTROL INPUT HIGH-SIDE (/INH) Pin (Pin 6)
Active low logic level control input for the high-side power FREDFET.
STATUS COMMUNICATION (FAULT) Pin (Pin 7)
This open Drain pin connects to an I/O port of the system micro-
controller to provide a status update. The pin should be connected to
SIGNAL GROUND if the function is not used.
SYSTEM MONITOR (SM) Pin (Pin 8)
This pin is a self-configuring system monitor input. It configures
itself into a high-voltage bus sense input if a resistor is connected to
the high-voltage bus at power-up. It configures itself into an external
temperature sense input if a resistance is connected to SYSTEM
GROUND at power-up. The pin should be connected to SIGNAL
GROUND if the function is not used.
DEVICE ID (ID) Pin (11)
This pin programs the device ID at power-up.
LS 24
HB
HB 16-19
NC 15
BPH 14
XH 13
HD
1 XL
2 IPH (NC)
3 SG
4 BPL
5 INL
6 /INH
7 FAULT
8 SM
9 NC
10 SG
11 ID
12 NC
PI-8292-120117
Figure 5.
Pin Configuration (Bottom View).
EXTERNAL CURRENT LIMIT HIGH-SIDE (XH) Pin (Pin 13)
This pin connects to a resistor to set the cycle-by-cycle current limit
for the high-side power FREDFET. The resistor is referenced to HALF
BRIDGE CONNECTION.
BYPASS HIGH-SIDE (BPH) Pin (Pin 14)
This pin connects to the external bypass capacitor for the high-side
FREDFET Gate driver. The capacitor is referenced to HALF BRIDGE
CONNECTION.
HALF-BRIDGE CONNECTION (HB) (Pin 16-19)
This pin connects to the Source of the high-side power FREDFET and
to the Drain of the low-side power FREDFET. It is also the reference
for the BYPASS HIGH-SIDE and the EXTERNAL CURRENT LIMIT
HIGH-SIDE pins.
LOW-SIDE SOURCE (LS) (Pin 24)
This pin is the low-side power FREDFET Source connection. It
connects to the SIGNAL GROUND through a Kelvin connection.
NOT CONNECTED (NC) Pins (Pins 2 (BRD116X only) 9, 12, 15)
This pin is not connected and should be left floating. Pin 2 only
applies to BRD116X.
4
Rev. F 11/18
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BridgeSwitch
BridgeSwitch Functional Description
BridgeSwitch combines two high-voltage power FREDFETs, gate
drivers and controllers into a single package. The FREDFETs are
connected in a half-bridge configuration where their diode structure
(ultra-soft and ultra-fast recovery) makes them ideal for hard-
switched inverter-based motor drivers.
To reduce external components, the drive controllers feature integrated
high-voltage current sources, allowing them to draw current directly
from the high-voltage DC Bus. The high-side controller provides
high-side status updates to the low-side controller which generates
an instantaneous phase-current output signal (BRD126X). This
unique capability allows the implementation of a sensor-less
motor-control scheme. The controllers also ensure that the FREDFET
turn-off is faster than turn-on resulting in an optimal balance
between thermal performance and EMI.
BridgeSwitch offers integrated fault protection and system level
monitoring via a bi-directional bussed single-wire status interface.
Internal fault protection includes cycle-by-cycle current limit for both
FREDFETs as well as two-level thermal overload protection.
BridgeSwitch offers sophisticated DC-bus sensing, providing four
undervoltage levels and one overvoltage level, and can also support
external sensors such as an NTC. Figure 3 shows the functional block
diagram of the device along with key features.
BYPASS LOW-SIDE Pin and HIGH-SIDE Pin Regulator
The BYPASS LOW-SIDE pin and the BYPASS HIGH-SIDE pin have
internal regulators that charge the BYPASS LOW-SIDE pin capacitor
and the BYPASS HIGH-SIDE pin capacitor to V
BPL
and V
BPH
, respec-
tively. A current source connected to HIGH-SIDE DRAIN charges the
BYPASS LOW-SIDE capacitor. Another current source connected to
HIGH-SIDE DRAIN charges the BYPASS HIGH-SIDE capacitor
whenever the low-side power FREDFET turns on. Both current sources
start charging once the HD pin voltage reaches V
HD(START)
(min. 50 V).
The BYPASS LOW-SIDE and the BYPASS HIGH-SIDE pins are the
internal supply voltage nodes for the low-side and the high-side
controllers and Gate drivers. When the low-side or the high-side
power FREDFETs are on, the device operates from the energy stored
in the BYPASS LOW-SIDE pin capacitor or the BYPASS HIGH-SIDE pin
capacitor, respectively.
In addition, there are shunt regulators clamping the BYPASS LOW-SIDE
pin to V
BPL(SHUNT)
and the BYPASS HIGH-SIDE pin to V
BPH(SHUNT)
when
current is provided to the BYPASS LOW-SIDE pin and the BYPASS
HIGH-SIDE pin from an external DC source through resistors (see
R
SL
and R
SH
in Figure 6). External supply voltage V
SUP
is greater than
bypass shunt regulator voltage V
BPX(SHUNT)
plus the voltage drop of
bootstrap diode D
SH
. A typical value is V
SUP
= 17 V. Resistors R
SL
and
R
SH
limit the external supply current to less than 12 mA (2-5 mA
recommended). Shorting BPL pins or BPH pins from separate devices
directly together is not recommended.
BYPASS LOW-SIDE Pin and HIGH-SIDE Pin
Undervoltage Threshold
The BYPASS LOW-SIDE pin and BYPASS HIGH-SIDE pin undervoltage
circuitries disable the respective power FREDFET when either the
BYPASS LOW-SIDE pin voltage or the BYPASS HIGH-SIDE pin voltage
drops below V
BPL
-V
BPL(HYST)
or V
BPH
-V
BPH(HYST)
, respectively, in steady-state
operation. Once either the BYPASS LOW-SIDE pin voltage or the
BYPASS HIGH-SIDE pin voltage fall below this threshold, it must rise
back up to V
BPL
or V
BPH
, respectively to enable power FREDFET switching.
BYPASS LOW-SIDE Pin and HIGH-SIDE Pins
Capacitor Selection
Capacitors connected to the BYPASS LOW-SIDE pin and BYPASS
HIGH-SIDE pin supply bias current for the low-side and the high-side
controller and deliver the required Gate charge for turning on the
low-side or the high-side power FREDFET. The BYPASS HIGH-SIDE pin
capacitor supplies the high-side controller bias current over a time
interval which is a function of the high-side commutation duty ratio and
PWM frequency. The recommended maximum voltage ripple at the
BYPASS HIGH-SIDE pin capacitor over this time interval is 250 mV. The
minimum required capacitance value for both bypass low-side and
bypass high-side is 0.33
mF.
The recommended bypass low-side
capacitance is 1
mF.
Given application operating conditions determine the required bypass
high-side capacitance to keep ripple voltage below 250 mV. Figure 7
depicts the minimum recommended BYPASS HIGH-SIDE pin capaci-
tance as function of high-side commutation duty ratio D
HS
and PWM
frequency.
f(PWM)
100
500
1000
6000
10000
16000
20000
PI-8309-080918
100
BPH Pin Capacitance (µF)
10
1
Minimum recommended value
HV Bus
BPH
HD
0.1
R
SH
D
SH
C
BPH
HB
BPL
0.01
SG
LS
V
SUP
+
-
R
SL
C
BPL
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Maximum High-Side Commutation Duty Ratio D
HS(MAX)
Figure 7.
BYPASS HIGH-SIDE Pin Capacitance vs. High-Side Commutation
Duty Ratio and PWM Frequency.
PI-8313-110518
Figure 6.
External BPL Pin and BPH Pin Power Supply Example.
Note that multilayer chip capacitors (MLCC) can exhibit a significant
DC bias characteristic. Selecting a BYPASS HIGH-SIDE pin capacitor
(according to Figure 7) needs to take the possible capacitance
reduction into account when biasing at V
BPH
. Refer to the respective
capacitor data sheet for details.
5
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Rev. F 11/18
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