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Renesas Electronics Corporation

Mid-Range Thermostat

Overview

Description

Mid-range thermostat systems build upon base thermostat systems with a cost-optimized UI, simplified voice control, and integrated sensors that switch relays for direct load control in an HVAC system. These systems then transmit measurement data to peer devices, such as a central thermostat and/or an outdoor unit.

This mid-range thermostat system can be leveraged for a wide range of needs—whether essential, enhanced, expanded, or extended. It comes in multiple variants, offering a wide range of functionalities and capabilities depending on the end application, to deliver scalable, smart, and sensor‑integrated systems for easy setup, control, and communication. Integrated Wi‑Fi® and Bluetooth® connect seamlessly to mobile apps and smart home ecosystems, enabling remote control and scheduling, while onboard sensors such as humidity and occupancy detection provide more accurate environmental awareness to optimize HVAC operation.

System Benefits:

  • Wi‑Fi 6 and Bluetooth connectivity enable remote monitoring, OTA updates, and smart home integration.
  • Easy installation and configuration via Bluetooth Low Energy (LE) and NFC eliminate the need for additional communications wiring by enabling wireless communication with other thermostats, sensors, and actuators through Wi‑Fi and Bluetooth LE.
  • Flexible HMI options—from simple voice command recognition and LCD visualization of critical information to sleek capacitive touch controls—enable intuitive, modern, and hands‑free user interaction.
  • Integrated sensors for temperature, humidity, and air quality enable precise environmental control through relay‑based load switching.
  • GreenPAK™ devices provide ultra‑low power latching relay control, reducing energy consumption while ensuring reliable HVAC switching.

Comparison

Applications

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Essential Thermostat with Core Functionality

WS151-1: WEBLine.226Line.239Line.214Connector Arrow.201Line Arrow.171Connector Arrow.27Sheet.105CrystalSheet.107Sheet.108Sheet.109Sheet.110Sheet.111Sheet.112Sheet.113Line.69Line.7027.12MHz27.12MHz27.12MHzBridge Rectifier.184Sheet.3Sheet.4Sheet.5Sheet.6Sheet.7Sheet.8Sheet.9Sheet.10Sheet.11Sheet.12Sheet.13Sheet.14Sheet.15Sheet.16Sheet.17Sheet.18LineConnector 1.160Buck RegulatorBuck RegulatorBuck RegulatorLine ArrowConnector 1.160.23Connector ArrowEnableEnableEnable24VAC24VAC24VAC5V5V5VGroundSheet.33Sheet.34Battery 1-CellSheet.36Sheet.37Line 1pt.1552Line 1pt.1583Line.40Connector Arrow.41Line Arrow.42VSYSVSYSVSYSBi-directionalAntennaSheet.56Sheet.57Sheet.58Sheet.59Sheet.60Line.83Line Arrow.84VSYSVSYSVSYSLine Bi-directional DottedNFC CoilNFC CoilNFC CoilSheet.94Transformer.324Line.841Line.842Sheet.98Inductor.300Sheet.100Sheet.101Sheet.102Line.104Touch KeySheet.119Sheet.120Sheet.121Sheet.122Sheet.123Sheet.124Sheet.125Sheet.126Sheet.127Line Arrow.128Touch InterfaceTouch InterfaceTouch InterfaceLCD/LED Segment DisplaySheet.132Sheet.133Sheet.134Sheet.135Sheet.136Sheet.137Sheet.138Sheet.139Sheet.140Sheet.141Sheet.142Sheet.143Sheet.144Sheet.145Sheet.146Sheet.147Sheet.148Sheet.149Sheet.150Sheet.151Sheet.152Sheet.153Sheet.154Sheet.155Sheet.156Sheet.157Sheet.158Sheet.159Sheet.160ONONONOFFOFFOFFSheet.163Sheet.164Sheet.165Sheet.166Sheet.167Sheet.168Sheet.169Sheet.170VSYSVSYSVSYSLine Arrow.173LCD DisplayLCD DisplayLCD DisplayTemperature & Humidity SensorTemperature & Humidity SensorTemperature & Humidity SensorIAQ SensorIAQ SensorIAQ SensorBi-directional.178Connected signals arrowConnected signals arrow.180Connected signals arrow.181Line Arrow.186MicrophoneSheet.190Sheet.191Keyword detection & voice controlKeyword Detection & Voice ControlKeyword Detection & Voice ControlVSYSVSYSVSYSLine Arrow.194VSYSVSYSVSYSLine Arrow.198Connector Arrow.200VSYSVSYSVSYSLine Arrow.203Latching RelaysLatching RelaysLatching RelaysLine Arrow.205Line Arrow.207VSYSVSYSVSYSLine.210Line Arrow.211PIR Motion SensorPIR Motion SensorPIR Motion SensorLine Arrow.213HVAC ControlHVAC ControlHVAC ControlWS151-1WS151-1WS151-1Battery ChargerBattery ChargerBattery ChargerBuck-BoostBuck-BoostBuck-BoostOp AmpOp AmpOp AmpRelay Control - GreenPAKRelay Control -GreenPAKRelay Control -GreenPAKComparatorComparatorComparatorOp AmpOp AmpOp AmpWireless ConnectivityWireless ConnectivityWireless ConnectivityNFC ReaderNFC ReaderNFC ReaderSheet.218MCUMCUMCUGPIOGPIOGPIOUARTUARTUARTSPISPISPICTSUCTSUCTSUSLCDCSLCDCSLCDCI2CI2CI2CGPIOGPIOGPIOGPIOGPIOGPIOADCADCADCCentral ThermostatCentral ThermostatCentral ThermostatAntenna.220Sheet.230Sheet.231Sheet.232Sheet.233Sheet.234Line Bi-directional Dotted.236Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connectivity (RS-485, CAN, Ethernet)Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connec...Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connectivity (RS-485, CAN, Ethernet)Line Bi-directional Dotted.238
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Enhanced Thermostat with Higher Display Resolution

WS151-2: WEBLine.83Connector Arrow.201Line Arrow.186Line Arrow.244Line Arrow.245Bridge Rectifier.184Sheet.49Sheet.50Sheet.51Sheet.52Sheet.53Sheet.54Sheet.55Sheet.56Sheet.57Sheet.58Sheet.59Sheet.60Sheet.61Sheet.62Sheet.63Sheet.64LineConnector 1.160Line ArrowConnector 1.2324VAC24VAC24VACLine Arrow.42VSYSVSYSVSYSBi-directionalAntennaSheet.93Sheet.94Sheet.95Sheet.96Sheet.97Wireless ConnectivityWireless ConnectivityWireless ConnectivityLine Arrow.84VSYSVSYSVSYSVSYSVSYSVSYSTemperature & Humidity SensorTemperature & Humidity SensorTemperature & Humidity SensorIAQ SensorIAQ SensorIAQ SensorConnected signals arrow.181Op AmpOp AmpOp AmpComparatorComparatorComparatorMicrophoneSheet.204Sheet.205Keyword Detection & Voice ControlKeyword Detection & Voice ControlKeyword Detection & Voice ControlVSYSVSYSVSYSLine Arrow.194VSYSVSYSVSYSLine Arrow.198Connector Arrow.200VSYSVSYSVSYSLine Arrow.203Line Arrow.205Line Arrow.207VSYSVSYSVSYSLine.210Line Arrow.211Line Arrow.213Line.214HVAC ControlHVAC ControlHVAC ControlWS151-2WS151-2WS151-2LCD (TFT-LCD)Block.120TFT LCD, OLED, or MIPI DisplayTFT LCD, OLED, or MIPI DisplayTFT LCD, OLED, or MIPI DisplayLCD (TFT-LCD).231Sheet.239Sheet.240Sheet.241Line Bi-directionalTouch InterfaceTouch InterfaceTouch InterfaceLCD DriverLCD DriverLCD DriverBacklightBacklightBacklightConnector ArrowLine Arrow.252VSYSVSYSVSYSBi-directional.257Connector dotted arrowConnector 1.160.259Buck RegulatorBuck RegulatorBuck RegulatorOp AmpOp AmpOp AmpPIR Motion SensorPIR Motion SensorPIR Motion SensorGreenPAKGreenPAKGreenPAKLatching RelaysLatching RelaysLatching RelaysSheet.262MCUMCUMCUUARTUARTUARTI2CI2CI2CGPIOGPIOGPIOGPIOGPIOGPIOADCADCADCI2CI2CI2CDisplay I/FDisplay I/FDisplay I/FPWMPWMPWMAntenna.220Sheet.265Sheet.266Sheet.267Sheet.268Sheet.269Line.226Line Bi-directional Dotted.227Line Bi-directional DottedWireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connectivity (RS-485, CAN, Ethernet)Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connec...Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connectivity (RS-485, CAN, Ethernet)Central ThermostatCentral ThermostatCentral Thermostat
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Expanded Thermostat with Scalable Smart Features

WS151-3: WEBConnector Arrow.201Line Arrow.171Connector Arrow.233Line.227Sheet.254CrystalSheet.256Sheet.257Sheet.258Sheet.259Sheet.260Sheet.261Sheet.262Line.69Line.7040MHz40MHz40MHzSheet.240CrystalSheet.242Sheet.243Sheet.244Sheet.245Sheet.246Sheet.247Sheet.248Line.69Line.7032MHz32MHz32MHzSheet.1CrystalSheet.3Sheet.4Sheet.5Sheet.6Sheet.7Sheet.8Sheet.9Line.69Line.7027.12MHz27.12MHz27.12MHzBridge Rectifier.184Sheet.26Sheet.27Sheet.28Sheet.29Sheet.30Sheet.31Sheet.32Sheet.33Sheet.34Sheet.35Sheet.36Sheet.37Sheet.38Sheet.39Sheet.40Sheet.41LineConnector 1.160Line ArrowConnector 1.2324VAC24VAC24VACGroundSheet.56Sheet.57Battery 1-CellSheet.59Sheet.60Line 1pt.1552Line 1pt.1583Line.40Line Bi-directional DottedNFC CoilNFC CoilNFC CoilNFC CoilSheet.96Transformer.324Line.841Line.842Sheet.100Inductor.300Sheet.102Sheet.103Sheet.104Line.103Line.104NFC ReaderNFC ReaderNFC ReaderTemperature & Humidity SensorTemperature & Humidity SensorTemperature & Humidity SensorIAQ SensorIAQ SensorIAQ SensorBi-directional.178Connected signals arrowConnected signals arrow.181Line Arrow.186MicrophoneSheet.181Sheet.182Keyword Detection & Voice ControlKeyword Detection & Voice ControlKeyword Detection & Voice ControlVSYSVSYSVSYSLine Arrow.194VSYSVSYSVSYSLine Arrow.187Connector Arrow.200VSYSVSYSVSYSLine Arrow.203Line Arrow.205Line Arrow.207VSYSVSYSVSYSLine Arrow.211Line Arrow.213Line.214HVAC ControlHVAC ControlHVAC ControlWS151-3WS151-3WS151-3VSYSVSYSVSYSLine Arrow.206Touch KeySheet.110Sheet.111Sheet.112Sheet.113Sheet.114Sheet.115Sheet.116Sheet.117Sheet.118Line Arrow.128Touch InterfaceTouch InterfaceTouch InterfaceLCD/LED Segment DisplaySheet.123Sheet.124Sheet.125Sheet.126Sheet.127Sheet.128Sheet.129Sheet.130Sheet.131Sheet.132Sheet.133Sheet.134Sheet.135Sheet.136Sheet.137Sheet.138Sheet.139Sheet.140Sheet.141Sheet.142Sheet.143Sheet.144Sheet.145Sheet.146Sheet.147Sheet.148Sheet.149Sheet.150Sheet.151ONONONOFFOFFOFFSheet.154Sheet.155Sheet.156Sheet.157Sheet.158Sheet.159Sheet.160Sheet.161VSYSVSYSVSYSLine Arrow.173Segment LCD DisplaySegment LCD DisplaySegment LCD DisplayVSYSVSYSVSYSConnector Arrow.2092x AA Batteries2x AA Batteries2x AA BatteriesConnector ArrowConnector Arrow.214CircleCircle.212VSYSVSYSVSYS3.3V3.3V3.3V3.3V3.3V3.3VConnector Arrow.218Connected signals arrow.219AntennaSheet.222Sheet.223Sheet.224Sheet.225Sheet.226Bi-directionalPSRAMPSRAMPSRAMBi-directional.236SPI NOR FlashSPI NOR FlashSPI NOR FlashBi-directional.239Buck RegulatorBuck RegulatorBuck RegulatorBuck-BoostBuck-BoostBuck-BoostORing SwitchORing SwitchORing SwitchOp AmpOp AmpOp AmpGreenPAKGreenPAKGreenPAKComparatorComparatorComparatorLatching RelaysLatching RelaysLatching RelaysOp AmpOp AmpOp AmpPIR Motion SensorPIR Motion SensorPIR Motion SensorSheet.268Wireless ConnectivityWireless ConnectivityWireless ConnectivitySPISPISPII2CI2CI2CGPIOGPIOGPIOGPIOGPIOGPIOADCADCADCPHYPHYPHYUARTUARTUARTIRQIRQIRQQSPIQSPIQSPIQSPIQSPIQSPIXTALXTALXTALXTALXTALXTALSheet.269MCUMCUMCUCTSUCTSUCTSUSLCDCSLCDCSLCDCUARTUARTUARTGPIOGPIOGPIOAntenna.220Sheet.272Sheet.273Sheet.274Sheet.275Sheet.276Line.226Line Bi-directional Dotted.278Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connectivity (RS-485, CAN, Ethernet)Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connec...Wireless Connectivity (Wi-Fi or Bluetooth LE) or Wired Connectivity (RS-485, CAN, Ethernet)Line Bi-directional Dotted.280Central ThermostatCentral ThermostatCentral Thermostat
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Extended Thermostat with Premium Features

WS151-4: WEBConnector Arrow.201Line Arrow.242Line Arrow.241Bridge Rectifier.184Sheet.3Sheet.4Sheet.5Sheet.6Sheet.7Sheet.8Sheet.9Sheet.10Sheet.11Sheet.12Sheet.13Sheet.14Sheet.15Sheet.16Sheet.17Sheet.18LineConnector 1.160Line ArrowConnector 1.160.2324VAC24VAC24VACLine Arrow.42VSYSVSYSVSYSBi-directionalAntennaSheet.56Sheet.57Sheet.58Sheet.59Sheet.60Wireless ConnectivityWireless ConnectivityWireless ConnectivityLine.83Line Arrow.84VSYSVSYSVSYSLine Bi-directional DottedNFC CoilNFC CoilNFC CoilNFC CoilSheet.94Transformer.324Line.841Line.842Sheet.98Inductor.300Sheet.100Sheet.101Sheet.102Line.103Line.104NFC ReaderNFC ReaderNFC ReaderTouch KeySheet.119Sheet.120Sheet.121Sheet.122Sheet.123Sheet.124Sheet.125Sheet.126Sheet.127VSYSVSYSVSYSTemperature & Humidity SensorTemperature & Humidity SensorTemperature & Humidity SensorIAQ SensorIAQ SensorIAQ SensorBi-directional.178Connected signals arrowLine Arrow.186MicrophoneSheet.190Sheet.191Keyword detection & voice controlKeyword Detection & Voice ControlKeyword Detection & Voice ControlVSYSVSYSVSYSLine Arrow.194VSYSVSYSVSYSLine Arrow.198Connector Arrow.200VSYSVSYSVSYSLine Arrow.203Latching RelaysLatching RelaysLatching RelaysLine Arrow.205Line Arrow.207VSYSVSYSVSYSLine.210Line Arrow.211Line Arrow.213Line.214HVAC ControlHVAC ControlHVAC ControlWS151-4WS151-4WS151-4Connector ArrowConnected signals arrow.219SPI NOR FlashSPI NOR FlashSPI NOR FlashConnector dotted double arrowLine Dotted ArrowBlock.120TFT LCD, OLED, or MIPI DisplayTFT LCD, OLED, or MIPI DisplayTFT LCD, OLED, or MIPI DisplaySheet.233Sheet.234Sheet.235Sheet.236Line Bi-directionalTouch InterfaceTouch InterfaceTouch InterfaceLCD DriverLCD DriverLCD DriverBacklightBacklightBacklightBi-directional.246Bi-directional.319RS-485RS-485RS-485Fan.321Sheet.322Sheet.323Sheet.324Sheet.325Sheet.326Sheet.327Sheet.328Sheet.329Sheet.330Sheet.331Line Bi-directional.332Antenna.333Sheet.334Sheet.335Sheet.336Sheet.337Sheet.338Line.339RS-485RS-485RS-485Fan.280Sheet.281Sheet.282Sheet.283Sheet.284Sheet.285Sheet.286Sheet.287Sheet.288Sheet.289Sheet.290Line Bi-directional.291Antenna.292Sheet.293Sheet.294Sheet.295Sheet.296Sheet.297Line.298Motor.299Sheet.300MMMLine Bi-directional.302FanFanFanCompressorCompressorCompressorFanFanFanHVAC/Heat Pump for Room/Indoor UnitHVAC/Heat Pump for Room/Indoor UnitHVAC/Heat Pump for Room/Indoor UnitHVAC/Heat Pump for Outdoor UnitHVAC/Heat Pump for Outdoor UnitHVAC/Heat Pump for Outdoor UnitLine Dotted Arrow.384Line Dotted Arrow.385Line Dotted Arrow.386Dotted LineConnector 1.160.388USB-CUSB-CUSB-CUSB-CSheet.395Sheet.396Sheet.397Sheet.398Sheet.399Sheet.400Sheet.401Sheet.402Sheet.403Sheet.404Sheet.405Sheet.406Sheet.407RS-485RS-485RS-485Connector dotted double arrow.411CAN PHYCAN PHYCAN PHYEthernet PHYEthernet PHYEthernet PHYConnector dotted double arrow.417Connector dotted double arrow.418Line Bi-directional Dotted.419Line Arrow.420VSYSVSYSVSYSBuck RegulatorBuck RegulatorBuck RegulatorRelay Control - GreenPAKRelay Control -GreenPAKRelay Control -GreenPAKComparatorComparatorComparatorOp AmpOp AmpOp AmpOp AmpOp AmpOp AmpPIR Motion SensorPIR Motion SensorPIR Motion SensorHVAC Controller with GUI & e-AIHVAC Controller with GUI & e-AIHVAC Controller with GUI & e-AIHVAC Controller with GUI & e-AIHVAC Controller with GUI & e-AIHVAC Controller with GUI & e-AIMotor ControlMotor ControlMotor ControlBi-directional.278Sheet.423Capacitive Touch MCUCapacitive Touch MCUCapacitive Touch MCUCTSUCTSUCTSUUARTUARTUARTSheet.424MCUMCUMCUSCISCISCISPISPISPII2CI2CI2CGPIOGPIOGPIOGPIOGPIOGPIOADCADCADCInternal Temp. SensorInternal Temp. SensorInternal Temp. SensorUARTUARTUARTI2CI2CI2CDisplay I/FDisplay I/FDisplay I/FPWMPWMPWMSCISCISCISCISCISCIEthernetEthernetEthernetUSBUSBUSBSheet.425Motor Control
EU188Motor Control EU188Motor ControlEU188Motor ControlMotor ControlMotor Control
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