Datasheet BridgeSwitch Family (Power Integrations) - 9

BridgeSwitch Device Over-Temperature Protection
The Phase Current Output Gain g and the resistor R connected to IPH IPH BridgeSwitch devices feature an integrated dual level thermal overload the PHASE CURRENT OUTPUT determine the voltage amplitude V at IPH protection. The device monitors the temperature of the low-side power a given phase current I : PHASE FREDFET every time it turns on. It will send a status update through the STATUS COMMUNICATION pin as soon as it reaches the lower VIPH = R IPH × IPHASE × gIPH Device Warning Temperature level T (see Table 4 for details). The Maximum permissible voltage amplitude of V is 3.0 V. WA IPH device disables FREDFET switching permanently once the FREDFET
External Current Sensing
temperature exceeds the Device Shutdown Temperature threshold T SD BRD116X devices support discrete low-side FREDFET current sensing to prevent device damage. Additional y it will report the over-tempera- through an external current sense resistor in series with the LS pin. ture fault through the FAULT pin. System level monitoring through the Figure 14 depicts one possible implementation example. SYSTEM MONITOR pin continues and the device will report any additional y occurring status changes through the STATUS COMMUNICA- Voltage V is a direct representation of the motor winding current SHUNT TION pin. The system MCU can re-enable FREDFET switching by I . Resistor R1 and R2 set the gain of external amplifier U1. MOTOR sending the fault latch reset command through the FAULT bus (see Resistor R3, C1, C2, and C3 provide noise filtering. Resistor R4 adds Table 7 for details). Alternatively operation may resume after a ful a DC offset V to the amplifier U1 output signal V . OFFSET OP power-up sequence initiated by the system MCU.
Phase Current Information Output
BridgeSwitch BRD126X devices feature instantaneous motor winding phase current information through a resistor connected to the PHASE
HD
CURRENT OUTPUT pin. The voltage across the smal signal resistor is a direct representation of the low-side power FREDFET Drain to Source channel current. The system MCU can digitize this voltage and use it
HB
for instance as an input for a chosen motor control algorithm. The vOFFSET device supports either independent phase current information through IMOTOR individual IPH pin resistors or a composite phase current signal through R4 interconnected IPH pins with a single resistor as shown in Figure 13.
SG LS
R3 U1 + R1 VSHUNT System µC V C3 C2 OP RSHUNT R2 C1
IPH IPH IPH
HB 1 HB 2 HB 3 PI-8565-120417 RIPH1 RIPH2 RIPH3 Figure 14. External Current Sense Example Circuit (BRD116X).
SG SG SG
R1 VOFFSET ×R3 + IMOTOR × RSHUNT × R4 a) VOP = a1 + R2 k R3 + R4 System µC The voltage differential V between SG and LS pins should not SHUNT exceed ±0.33 V. Current sense resistor R in series with the LS pin SHUNT has to be sized accordingly.
System Monitor Input IPH IPH IPH
BridgeSwitch features system level monitoring through the SYSTEM HB 1 HB 2 HB 3 MONITOR input. The SM pin supports monitoring either the R high-voltage (HV) DC bus (see Figure 14) or the temperature of an IPH1 external component through an NTC thermistor (see Figure 16).
SG SG SG
The SM pin is self-configuring. It automatical y detects the type of external connection and locks in the respective circuitry configuration at power-up. b) PI-8301a-040517
High-Voltage DC Bus Monitoring
The SYSTEM MONITOR pin continuously monitors the high-voltage DC Figure 13. Phase Current Information through IPH Pin with BRD126X a) bus voltage level by sensing the current into this pin. The current I Individual Phase Currents b) Composite Phase Current. SM into the SM pin is a direct representation of the high-voltage bus voltage level V : BUS I VBUS VSM SM = – RHV1
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Rev. I 01/20 www.power.com Document Outline Product Highlights Description Output Power Table Pin Functional Description BridgeSwitch Functional Description Application Example PCB Design Guidelines Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics Typical Performance Characteristics inSOP-24C Package Drawing Package Marking Part Ordering and MSL Table ESD and Latch-Up Table Part Ordering Information